It's been said that every actor secretly wants to be a rock star, to hear the cheers of the crowd, to hold a live audience in the palm of their hand. Maybe. But what's definitely true is that some actors probably could be.

It might be because I work for MTV, or because there have been so many movie musicals and movies about music released recently. Maybe it's simply that some things are better expressed through music. But over the last few months a surprising number of celebrities — from Ben Stiller to John Travolta to Jackie Chan to the Rock — have decided to break into song for our cameras.

OK, a lot of the time it's because we ask them to. But then, not one of them ever needed to be asked twice. Should they toot or stay mute? Turn up your speakers and give a listen to the unique musical stylings of the following celebrities:

Ben Stiller

The song: "Telephone Line" (Electric Light Orchestra)

The setup: In Stiller's "The Heartbreak Kid,""The Heartbreak Kid," a trip down to Mexico with his new bride turns disastrous when she begins obnoxiously singing every song on the radio. We wanted to know if he's ever been caught awkwardly singing along to a particularly bad song.

How does he rate?: Stiller surprises with a powerful falsetto but lacks the vocal commitment to truly pull off ELO's stirring lyrics ("ooh, ooh, ooh").

Chris Tucker and Jackie Chan

The song: "The Closer I Get to You" (a song performed by everyone from Beyoncé to Luther Vandross)

The setup: In their third go-round in the "Rush Hour" universe, third go-round in the "Rush Hour" universe, Chan and Tucker infiltrate a Parisian nightclub to find a witness. Soon, they're caught onstage mid-performance and must improvise a song. We wanted to know who the better singer was.

How do they rate?: Near-perfect timing for an impromptu performance. Harmonies need more work, as does lyric memory.

What you didn't see: Immediately after finishing their duet, Tucker jokes that it's part of their proposed new sequel, "Brokeback Rush Hour."

John Travolta

The song: "You're the One That I Want" (from the "Grease" soundtrack)

The setup: We wanted to know if "Hairspray" "Hairspray" co-star Nikki Blonsky ever got nervous singing alongside a movie-musical legend. She told us about a time, late at night in frigid temperatures, when she happened to say, "I got chills," and Travolta broke out in song.

How does he rate?: C'mon? Really? It's Danny freaking Zuko.

What you didn't see: Our failed attempt to get him to do the hand jive.

Dwayne "the Rock" Johnson and Madison Pettis

The song: "Are You Lonesome Tonight?" (Elvis Presley)

The setup: In "The Game Plan," Johnson sings Elvis to coax Madison's character out of her room.

How do they rate?: Bonus points for use of jazz hands.

What you didn't see: Later on, the pair danced the robot.

The cast and crew of "Walk Hard: The Dewey Cox Story"

The songs: Tim Meadows - "Psycho Killer" (Talking Heads), John C. Reilly - "My Way" (Frank Sinatra), Judd Apatow - "Baba O'Riley" (the Who), Matt Besser - "I Will Always Love You" (Dolly Parton)

The setup: The main story thread in "Walk Hard" is Dewey Cox's lifelong struggle to create an all-encompassing opus that will sum up his career. We wanted to know what the film's cast and crew would choose as their theme songs.

How do they rate?: Their singing was almost uniformly good, although we question some of the song choices given our request. "Psycho Killer," Mr. Meadows? Qu'est-ce que c'est, sir? Qu'est-ce que c'est indeed?

What you didn't see: After singing "Baba O'Riley," Judd Apatow improvised the distinctive synth melody.

Who's the best? Who should stick to their day job? Let us know below.

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