Peter Dinklage's hidden 'Seinfeld' cameo, and 7 other surprising celebrity voiceovers

Some celebrity voices you can recognize anywhere -- Morgan Freeman's, Christopher Walken's, James Earl Jones'. Others tend to sneak up on you when you're not looking. In fact, some may have even past you clear by. Here are seven voices that you will be surprised to know were provided by stars you actually know:

Peter Dinklage - "Seinfeld"

Back in 1995, Dinklage provided the voice of Elaine's telephone wake-up guy, James, in the seventh season of "Seinfeld." Peter Dinklage was still 16 years away from "Game of Thrones" but only needed a pair of pipes to charm.

And to this day, the actor plays Tyrion Lannister hasn't lost his voice-over talent: more recently, he narrated the teaser for the Sochi Olympics.

Julianne Moore, "Eagle Eye"

In the 2008 techno-thriller "Eagle Eye," Julianne Moore voiced an anonymous caller who coerces a couple (Shia LaBeouf and Michelle Monaghan) into possibly carrying out terrorist activities.

As it turns out, she is the voice of the Department of Defense's Autonomous Reconnaissance Intelligence Integration Analyst (ARIIA) supercomputer. Pff, that's so predicatable.

Bruce Willis, "Look Who's Talking"

He may be more familiar as a gun-toting off-duty cop in the "Die Hard" franchise, but Bruce Willis actually provided the voice of a newborn back in 1989.

Yes, that's him voicing Kirstie Alley's baby boy Mikey in "Look Who's Talking."

Kathleen Turner, "Who Framed Roger Rabbit?"

As the impossibly curvy red-headed toon in "Who Framed Roger Rabbit?" Kathleen Turner had a body to die for and a voice to match.

In the guise of lounge singer Jessica Rabbit, the "Californication" star said, "I'm not bad, I'm just drawn that way." But her pipes didn't hurt, either.

Vin Diesel, "The Iron Giant"

Long before he was Groot in "Guardians of the Galaxy," Vin Diesel lent his voice to the titular hero in "The Iron Giant" in 1999.

He didn't say many words in that film either, but he certainly expressed a range of feeling as the sensitive machine.

Howie Mandel, "Gremlins"

Gizmo was so adorable that it was easy to forget that his voice was done by a human.

As it turns out, Canadian comedian Howie Mandel, better known as the host of "Deal or No Deal," actually provided the voice of the fuzzy cutie in the 1984 blockbister and its follow-up.

Michael Cera, "The Berenstein Bears"

At the age of 14, a year before he rose to fame as George Michael in "Arrested Development," Michael Cera provided the voice of brother bear in "The Berenstein Bears."

The Canadian actor's casting isn't much of a surprise when you consider the series was produced by the Canadian animation company Nelvana.

Kevin Spacey, "Moon"

The 2009 sci fi thriller was such a complex tale that you may not have noticed that one of Hollywood's best actors had a pretty significant role.

Spacey provided the voice of GERTY, the friendly but secretive AI that helps astronaut Sam (Sam Rockwell) complete his work on the moon. Spacey reportedly refused to agree to lend his voice until he'd seen the completed film - but once he did, he loved "Moon" so much that he recorded his part in less than a day.

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