WARNING: The following contains major spoilers for Men in Black: International, in theaters now.

With the fourth film in the franchise, director F. Gary Gray's Men in Black: International, the sci-fi action (and comedy) heads overseas, as Chris Hemsworth's Agent H and Tessa Thompson's Agent M try to recover a super-weapon in Morocco, London and Paris.

RELATED: Men in Black: International Fails to Reignite the Franchise Spark

Still, as much as the franchise treads new ground, there are callbacks and Easter eggs to the days of Will Smith's Agent J and Tommy Lee Jones' Agent K, who protected New York City from extraterrestrial threats.

FRANK THE PUG

In the original trilogy, Frank serves as an informant for J and K, holding integral information on the swath of aliens who use New York City as a galactic airport. He even gets tangled up with villains like Serleena in Men in Black II, and eventually joins the agency because of his expertise.

Men in Black: International gives Frank (still voiced by Tim Blaney) a brief cameo when Thompson's Molly (as she was known before she officially joined the agency) sneaks into the New York headquarters. She enters the building and fakes knowledge of refugee pick-up while the doorman reads the paper. However, Frank is guarding the door with him, and when Molly takes the elevator to the main hub, the pug urges the doorman to notify security of the "amateur" breach.

THE WORM GUYS

After Molly is intercepted, she reveals to the head of the head of the New York office, Agent O (Emma Thompson), that she saw her parents get neuralized after a close encounter as a child, and since then her goal has been to join the agency. She begs O for a chance to don the black suit, and she's granted a probationary period, as she has the necessary qualifications, and no life to leave behind.

RELATED: Every Men in Black Movie Ranked, According to Critics

When M boards the agency's high-tech train for her London assignment, we see a couple of the Worm Guys. As usual, they're discussing where they're going to party tonight, sticking to the same kind of banter depicted in the trilogy, where they often hit up J to partake in less-than-savory extracurricular activities. They don't get much speaking time, but it shows they haven't changed one bit.

THE NOISY CRICKET

While most agents carry a Series-7 Deatomizer, fans might remember K giving J a small pistol called the Noisy Cricket, instructing him to never point it at him. We thought it was a joke until J used the weapon to hunt down Edgar the Cockroach, and we witnessed the Noisy Cricket's immense firepower. It may have be small, but it has quite the kickback with its destructive blasts.

Here, when M suits up for the first time, she's given an array of weaponry options, and ponders long and hard which handgun to take. Her handler offers a case containing new versions of the Noisy Cricket, but she simply stares into the camera with a sly grin as if to say: This is J's weapon. She passes on the handgun, revealing to her superior it's not really her style.

THE RED BUTTON

Fans might recall that, in the 1997 original, K warned J never to press the red button on their car's gear shift. Later, however, J had to press it as they chased the Cockroach, transforming the car into what's basically a rocket on the ground. It was also able to ride the walls of the Queens-Midtown Tunnel because of its mega-thrusters.

RELATED: Men in Black: International's Villainous Twist, Explained

As H and M pursue the super-weapon in Men in Black: International, they learn it's destined for a species called the Hive. They jump into H's car, where he urges M to push the red button -- one that's a bit more advanced. This time it transforms the car into a jet able to travel across Europe. The ride is much smoother this time around, indicating MiB has advanced with the times.

THE DYNAMIC DUO

When M is briefed on the organization's history by High T (Liam Neeson), head of the London branch, we see a series of paintings that immortalize the agency's most decorated field officers. There's H and T fighting off the Hive from the beginning of the movie, but we also spot one with J and K in battle.

RELATED: How Men in Black: International Changes the Agency's History

It's a tribute to the duo fighting the giant Cockroach at Flushing Meadows in 1997's Men in Black, one of the defining moments of the franchise.

Now in theaters nationwide, director F. Gary Gray's Men in Black: International stars Chris Hemsworth, Tessa Thompson, Rebecca Ferguson, Kumail Nanjiani, Rafe Spall, Laurent Bourgeois, and Larry Bourgeois, with Emma Thompson and Liam Neeson.