The Iron Giant, from the film of the same name. Before he even became famous, the guy from Fast Five voiced the title character in the timeless story of the friendship between a boy and a giant alien robot.

Granted, his voice is pretty filtered and his lines are mostly grunts and monosyllables, but Diesel actually did a pretty good job here. Unsurprisingly, The Iron Giant is his highest rated IMDB credit after Saving Private Ryan, which doesn't even count because we're pretty sure he got killed in like the first 20 minutes. Anyway, here's some footage of Diesel recording the Giant's voice.

The Iron Giant's director, Brad Bird, went on to make Pixar's Ratatouille and The Incredibles -- but sadly he didn't cast Diesel in either of them.

But he was also ...

The same actor also voiced Shredder from the Teenage Mutant Ninja Turtles cartoon.

That's right, for over 100 episodes, the man best known for playing a dull, conservative judge/socialite also lent his voice to an Asian ninja master best known for living inside a giant mechanical eyeball and hanging out with a hideous man-hog and a disembodied brain. Also, for being a huge jerk. If you grew up in the 90s, this is the closest thing to finding out your grandpa and that bully from school were actually the same person all along.

Here's Avery talking about Shredder and the hidden levels of profundity within the character, plus openly admitting the interaction between him and Krang was played "like an old married couple."

If that's his idea of an old married couple, we're thinking things turned pretty bizarre in the Banks mansion after Will, Carlton and the girls left.

You know him best as ...

Between 1984 and 1992, Earle Hyman played Bill Cosby's father in The Cosby Show, despite being only 11 years older than the star (the conception could have been a touching flashback episode, right?). Grandpa Russell "Slide" Huxtable was a trombone player, a proud graduate of Hillman College and a really bad buyer of sweaters.

But he was also ...

Panthro from the Thundercats. At the very same time he was playing Russell Huxtable, Earle Hyman was also moonlighting in animation as a humanoid warrior feline from outer space.

Panthro was the resident mechanic in the Thundercats and also the least clothed one after Snarf. We have no idea what it is with aging African-American male actors playing martial artists on cartoons in the 1980s, but this does raise an interesting question: Who would win in a nunchaku throwdown -- Uncle Phil or Grandpa Huxtable?

We will never be able to watch Panthro in action again without imagining Cosby's dad in the same situation.

Earle Hyman talked about voicing Panthro in this podcast (starting at around 19:00), and he says it was an easy job because he just pretended he was talking to his cats, which makes us think he probably misunderstood the plot of the series just a little bit.

Before you start complaining about Hollywood raping your childhood with all these goddamned celebrity-studded remakes, Fergie was the one of original Sallys. As Stacy Ferguson, she voiced the character in two classic Peanuts movies and The Charlie Brown and Snoopy Show (where she also voiced Patty), starting when she was only 9. Here's what she sounded like back then.

And apparently she can still do that voice, which means that if they did a big-budget CGI Peanuts movie, casting Fergie would be a good decision for once.

The voice of Winston Zeddemore in The Real Ghostbusters, the character originally played by Ernie Hudson in the movies.

It's strange to think that back in that bizarro reality known as the 1980s, Ernie "Beverly Hills Chihuahua 2" Hudson was apparently too big a star to be bothered to appear in a little animated show, so they had to get Arsenio freakin' Hall to do an impression of him. Of course, Arsenio was a practically unknown stand-up comedian at the time, still a few years away from his big break as Eddie Murphy's co-star in Coming to America. This might explain why they also had him doing some of the bumpers for the show.

Arsenio hasn't done a lot of voice-over work since he became famous, but we think a return to animation is inevitable. By our watch, he's about 10 years away from being cast in a cartoon as some sort of mutant martial artist, possibly with spikes coming out of his costume.

For years, Howie Mandel was primarily known as an annoying stand-up comedian before becoming even better known as an annoying game show host. You may also remember him as that annoying guy from St. Elsewhere and the hidden camera segments in The Tonight Show. Had he died in 1989, he would have probably been remembered as that guy who blew up surgical gloves on his head.

We find him really annoying, is what we're saying here.

But he was also ...

Via ActionFlickChick.com

Gizmo, the cute hamster/monkey hybrid from the movie Gremlins. Remember those adorable sounds Gizmo used to make? That's 100 percent Howie Mandel.

That's not all: Mandel also worked in Muppet Babies for a while, providing voices for characters like Baby Animal and Skeeter (Scooter's sister) ... which, of course, was the exact same voice he'd later use for Bobby in Bobby's World, as he's happy to admit.

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So it turns we have that guy from Deal or No Deal to thank for a huge chunk of our childhoods. We ... we need to sit down for a moment.

You know him best as ...

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Detective Lennie Briscoe was probably the most recognizable face of Law & Order, having starred in 11 seasons of the show, plus several guest spots in the interminable list of spin-offs. As Briscoe, Orbach played the classic detective with the obligatory alcohol addiction and the messed up dysfunctional family. Because of his alcoholism, his daughter grew up to be a meth addict and was murdered by a drug dealer. Of course, you could probably tell all that stuff just by looking at the permanent "Goddammit, son" expression on Orbach's face.

But he was also ...

Lumiere, the talking candlestick from Disney's Beauty and the Beast. They even look alike:

Via Disney-Clipart.com

And yes, this means that was Detective Briscoe's singing voice in some of those musical numbers (sometimes as the lead singer), like the one where the whole dining room sings "Be Our Guest" to Belle.

In fact, before he even starred in Law & Order, Orbach was already an accomplished Broadway actor. He won a Tony award for Promises, Promises and was nominated his role in the original production of Chicago. If for some reason you still can't picture it, here's Orbach singing and dancing to the music of Beauty and the Beast for the 1992 Academy Awards ceremony.

Bear in mind that this was right before he joined the cast of Law & Order. A few years of chasing down child-killing drug dealers and saying, "I'm just trying to do my job here!" could turn anyone a little dour.

Flea is known for being in the favorite band of at least one guy in your college dorm who didn't know how to turn his stereo down, and for never ever wearing a shirt. Or anything but tube socks, at one point in his career. Flea is the douchiest looking member of the Red Hot Chili Peppers, mainly due to the fact that he appears to be the son of Dee Dee Ramone and Clint Howard.

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If, like us, your instinctual reaction to seeing Flea's face is to hide your lunch money, you might be surprised by the next part.

But he was also ...

Donnie from Nickelodeon's The Wild Thornberrys.

Donnie was a feral boy raised by orangutans, and we're guessing that what attracted Flea to the part was their shared fashion sense. Also, the whole job consisted of standing in front of a microphone and letting out incoherent grunts for 20 minutes, which was probably a refreshing break from the carefully crafted poetry of the Chili Peppers. Here's Flea totally killing it as Donnie in The Wild Thornberrys:

Flea has actually been an actor since the 80s, somehow finding his way into some of our favorite movies: he was one of the nihilists in The Big Lebowski, a hippie in Fear and Loathing in Las Vegas and the asshole who taunts Marty in Back to the Future Part II and Part III.

To read more from Jim Ciscell check out American Slacker.

For more surprising celebrity side jobs, check out 7 Celebrities Who Had Badass Careers You Didn't Know About and The 7 Most WTF Post-Fame Celebrity Careers.

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