Captain Planet and the Planeteers was known for two things, it's noble, if not a bit ham-fisted environmentalist message, and celebrity voices. Most of the villains in the series were, at some point, voiced by big-name celebrities of the time, and the show had plenty of other guest stars. Captain Planet was produced by Turner and Hanna-Barbera, lasting six seasons from 1990-1996. It starred the eponymous Captain Planet, a superhero formed by the combined elemental powers of the Planeteers, teenagers from all around the world chosen to protect Earth from all forms of pollution. The show was a powerful tool in environmental awareness, which might have been why so many celebrities got involved.

RELATED: 15 Times An Actor Played Two Roles In The MCU (And You Never Even Realized)

Villains and guest stars were often voiced by famous celebrities of the time, the actors joining the show to help boost the popularity of Captain Planet and its message. Captain Planet and the Planeteers was a powerhouse of famous voices, of both acting and voice acting fame, something that not everyone might know. Because of this, we decided to go back and look at all the famous actors and celebrities who provided voices for the environmentalist show. Here's our list of the 15 celebrities you NEVER knew voiced characters on Captain Planet and the Planeteers.

15 JEFF GOLDBLUM — VERMINOUS SKUMM

Before he was the Grandmaster in Thor: Ragnarock, before he was the spokesman for apartments.com, heck, before he was even the beloved Dr. Malcolm in Jurassic Park, Jeff Goldblum voiced a villain on Captain Planet and the Planeteers. Goldblum provided the voice for Verminous Skumm, a half-rat, half-human mutant who can control an army of rats. Verminous Skumm was meant to represent crime and the spread of disease through poor sanitary conditions.

Goldblum only voiced the character for the first seasons, presumably to move on to bigger roles than a villainous rat-man on a kid's cartoon. Since his time as the disgusting Verminous Skumm was short, fans of Goldblum's might not have known of this voice role. Perhaps if Captain Planet get's a reboot, Goldblum might reprise his role.

14 NEIL PATRICK HARRIS — TODD ANDREWS

Speaking of Verminous Skumm, he loves to spread disease, and in one episode, he tried to perpetuate the spreading of HIV and AIDS. Captain Planet dealt with issues like this to better help educate the public, which was the theme of this particular episode, titled "A Formula For Hate." Back when he 19 years old, Neil Patrick Harris provided for the voice for the focus character of this episode, Todd Andrews.

In the episode, Todd, a high school basketball player, is diagnosed with HIV, and the news spreads fast. Thanks to Verminous Skumm, fear, panic and misinformation begin to spread around Todd's friends and family, which Skumm believes will make HIV and AIDS spread faster. Luckily, Captain Planet saves the day by informing the people of the facts of HIV/AIDS, stopping the panic and misinformation.

13 WHOOPI GOLDBERG — GAIA

Whoopi Goldberg has had a long, illustrious career in the entertainment industry, starring in films, television and yes, cartoons like Captain Planet. Goldberg voiced the spirit of Earth herself, Gaia, the guardian of nature who gave the Planeteers their rings and powers. Like Goldblum, Goldberg eventually left the role, funnily enough being replaced by Lois Lane actress Margot Kidder.

For the first three seasons of the show, Goldberg provided the voice for Gaia, a modern depiction of the ancient Greek personification of the Earth. Gaia's health and well being was connected to the Earth; she hurt when it was hurt, and when she wakes from her 100 year slumber, she is devastated to find the Earth in such a state of pollution, leading her to gather the Planeteers.

12 TIM CURRY — MAL

Tim Curry is a pop culture icon. He's known for various cult classics including The Rocky Horror Picture Show as well as his extensive voice acting roles. One of Curry's earlier voice roles was in Captain Planet as MAL, Dr. Blight's evil supercomputer AI. Curry actually took over the role from David Rappaport, who sadly died in 1990. Curry portrayed the HAL parody for the remaining five seasons of the show.

MAL was used by Dr. Blight, who reprogrammed him from a game-loving AI, to help enact her evil plans. Though, MAL, with his supercomputer intelligence, often argued that her plans would not work, which was usually correct. Even weirder, Blight and MAL seemed to flirt with each other at times, now that's just plain awkward.

11 DANNY GLOVER — PROFESSOR APOLLO

If there's one thing that Danny Glover is known for, it's his famous role in the Lethal Weapon film series as Roger Murtaugh. He's especially known for Murtaugh's famous catchphrase, "I'm too old for this shit," also used by Glover in other roles. Amongst his many beloved roles, Glover also guest starred on the Captain Planet episode, "Isle of Solar Energy."

In the episode, the Planeteers meet Professor Apollo, played by Glover, who is doing research on solar energy. However, things get out of hand when Professor Apollo's lab assistant is revealed to be Leadsuit, Duke Nukem's evil underling. The Planeteers must stop Leadsuit and Duke Nukem from using Professor Apollo's research to make a radioactive weapon. Fortunately, the Planeteers are able to save the day and preserve Dr. Apollo's vital research.

10 ED ASNER — HOGGISH GREEDLY

Former president of the Screen Actors Guild Ed Asner has had a long career in film and television. Asner has won seven Emmys, the most awards for a male actor in Emmy history, and is most famous for his role as Lou Grant on The Mary Tyler Moore Show and the spinoff series, Lou Grant. Asner is also known for portraying Carl in Pixar's Up, but this wasn't his first voice acting role.

Asner provided the voice for one of Captain Planet's main villains, Hoggish Greedly. Hoggish was the first villain Captain Planet and the Planeteers faced in the series. He is a pig mutant who was meant to portray the dangers of greed and overconsumption, always wanting more and more. Unlike some of the other entries, Asner voiced the character for the entirety of the series.

9 MARTIN SHEEN — SLY SLUDGE

The very last of the Eco-Villains to be introduced in the series was Sly Sludge, a garbage man with little to no moral compass. Sly Sludge, who's name kind of sounds like a '90s metal band, represented short-term thinking, the antithesis of reusable and recyclable resources. Sly is joined by his two underlings, Ooze and Tank Flusher III, his super strong servant.

So who voices this literal garbage man? That's right, none other than Martin Sheen. Comic book moviegoers might know Sheen as Uncle Ben in The Amazing Spider-Man, but he's also had a long, LONG career in film as well as a successful career in documentary narration. Sheen portrayed Sly Sludge for three seasons before being replaced by veteran voice actor Jim Cummings.

8 MEG RYAN — DR. BLIGHT

Admit it, despite her literally being the epitome of pollution-based evil, you definitely had a crush on Dr. Blight. Sure, she had that lab-accident scar, but she hid it with a sultry hairstyle. Not to mention she had that skin-tight bodysuit and flirty nature. This '90s cartoon crush was voiced by none other than Meg Ryan, who, unlike Dr. Blight, is politically active in protecting the environment.

Meg Ryan is best known for roles like When Harry Met Sally as well as a long list of romantic comedies in the '90s and early '00s. She was also the voice of Anastasia in the animated musical of the same name. Ryan's work eventually led her to leave the voice role of Dr. Blight after the first season, being replaced by Mary Kay Bergman, who portrayed the mad scientist for the rest of the show's run.

7 LEVAR BURTON — KWAME

LeVar Burton has a lot of pop culture cred, from portraying Geordi La Forge on Star Trek: The Next Generation to his role as the host of Reading Rainbow and even his portrayal of Kunta Kinte on Roots. Burton has also done quite a bit of directing, including a couple of episodes of later iterations of Star Trek. Burton has also done a bit of voice work, including Kwame on Captain Planet and the Planeteers.

A teenager from a tribe in Ghana, Kwame was the leader of the Planeteers, possessing the power of Earth. With his power, Kwame was able to manipulate rocks, dirt and plant life. Recently, LeVar Burton reprised his role, along with Captain Planet voice actor David Corburn, in a special episode of the Cartoon Network series OK K.O.! Let's Be Heroes.

6 PHYLLIS DILLER — JANE GOODAIR

With a name like Jane Goodair, one might expect you to dedicate your life to providing clean-air cars for the world. This is exactly what Jane Goodair does in the Captain Planet episode, "Smog Hog." In the episode, Jane is about to release her first Goodair Sedan when Hoggish Greedly takes over her factory to mass-produce his gas-guzzling "Road Hog," and the Planeteers must stop his smog-producing venture.

Jane Goodair was voiced by the one and only Phyllis Diller, a comedian best known for her outlandish stage presence and self-deprecating style of humor. Diller also had countless television appearances, doing some animation voice work later in her career, including one-time roles on The Power Puff Girls and Hey Arnold!

5 JOHN RATZENBERGER — RIGGER

You might not recognize his name, but if you hear his voice, you'd know exactly who John Ratzenberger is. Ratzenberger has voiced a character in every single Pixar film ever, ranging from small roles like The Abominable Snowman in Monsters, Inc. to main characters Hamm in Toy Story. Of his many Pixar roles, Ratzenberger said his favorite was P.T. Flea because he found it fun to play an irritable, always on edge character who goes into random fits of rage.

But Ratzenberger has had more than Pixar roles, and though we can't say wether or not it was his favorite, he's also done voice work for Captain Planet as Rigger, a henchman of Hoggish Greedly. Rigger seemed to be less of a dedicated follower and more of an employee of Greedly, only working for the villain because no one else would hire him.

4 DEAN STOCKWELL — DUKE NUKEM

Not to be confused with the video game character of the same name, Duke Nukem was one of the main Eco-Villains of the series. Duke is a radioactive mutant who feeds off of toxic waste, using his nuclear powers to bring disaster in his wake. He's also got one heck of a fashion sense, sporting a look akin to a tourist on a tropical vacation.

The man behind the voice of this radioactive villain was none other than, Dean Stockwell. Stockwell is of course known for playing Al on Quantum Leap, which got him nominated for three Emmys. He has been acting since he was nine years old, leading into a career of over 70 years. However, Stockwell only voiced Duke Nukem for the first two seasons of the show before being replaced by Maurice LaMarche.

3 JAMES COBURN — LOOTEN PLUNDER

It's funny that the Eco-Villains are made up of seven members, since it wouldn't be the first time that James Coburn was part of an ensemble cast of seven characters. We are of course talking about Coburn's role in The Magnificent Seven, a western based on Akira Kurosawa's Seven Samurai. This is but one of Coburn's many roles in his 45 year career, adding up to over 100 TV roles and over 70 films.

In Captain Planet and the Planeteers, Coburn portrayed Looten Plunder. Plunder's character, as his name implies, represents corporate greed, using cutthroat corporate tactics to steal money and resources from the people. Like most of the entries on this list, Coburn only voiced the character for two seasons before being replaced, Ed Gilbert taking over in latter seasons.

2 MALCOM MCDOWELL & STING — ZARM

Best known for his role as Alex DeLarge in A Clockwork Orange, Malcolm McDowell has been working as an actor since 1964. Sting is perhaps an even bigger celebrity, a musician best known as the frontman of The Police as well as his solo career. What do these tow have in common? Well, they both voiced the same character on Captain Planet.

McDowell and Sting both portrayed Zarm, the previous spirit of the Earth, Zarm. Zarm left Gaia and Earth to explore other world, straying from his ways and seeking to destroy other planets. For the first two seasons of Captain Planet, Sting provided the voice of Zarm before David Warner took over for season three. Afterwards, Warner left and the role was taken up by McDowell, who has had a long career of playing villains.

1 TOM CRUISE — (ALMOST) CAPTAIN PLANET

Earth, Fire, Wind, Water, Heart! By these powers combined, he is, Tom Cruise? Fans of Captain Planet know that the Captain himself is voiced by David Coburn (no relation to James Coburn), but he wasn't the first choice. The eco-hero was originally intended to be voiced by Tom Cruise. Cruise was all set to play the character, but pulled out at the last minute for unknown reasons.

As neat as this fun fact is, we're kind of glad that Cruise never took the role, since he might not embody everything the character stands for. In 2006, there was a report stating Cruise spent a million dollars on fuel for his various vehicles. Not exactly what you want to hear from the prospective voice of Captain Planet.

Can you think of any other surprise voice roles in Captain Planet? Let us know in the comments!