It’s a regular plant versus zombies brawl in a new clip for Cartoon Network’s “Justice League Action” television series, which pits Swamp Thing against Solomon Grundy. And, no, your ears don’t deceive you -- that’s Mark Hamill of “Star Wars” and “Batman: The Animated Series” fame providing the sweet, weedy vocals for the marshland’s defender.

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The clip, from the show's upcoming “Zombie King” episode, shows Solomon Grundy getting ready to march on a nearby city, having raised an army of the undead. Of course, Swamp Thing has a thing or two to say about this, ever the vigilant defender of all things weedy and vine encased that he is. The two brawl it out, but in the end a bested Swamp Thing is forced to call in aid from the Justice League.

Hamill is perhaps best known for his role as Luke Skywalker in the original “Star Wars” trilogy, a role he reprised for the 2015 “Star Wars: The Force Awakens.” But he is also an accomplished voice actor with decades of work under his belt.

Hamill provided the iconic voice of the Joker in “Batman: The Animated Series,” which ran from 1992 to 1995. His interpretation of the Clown Prince of Crime was so well-received that he went on to voice the character in numerous spinoffs of the series and subsequent animated movies, as well as the more recent “Batman: Arkham” video game series by Rocksteady Studios.

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“Zombie King” airs on Cartoon Network on Saturday, February 4 at 7:30 AM. “Justice League Action” is a production of Warner Bros. Animation and DC Entertainment starring Kevin Conroy, Rachel Kimsey and Jason J. Lewis.