Sometimes an actor surprises us by singing in a movie -- Gwyneth Paltrow in 'Duets' or Joseph Gordon-Levitt in '(500) Days of Summer' are good examples.
But what's even better is when a celebrity surprises everyone in a karaoke bar by belting out a tune in real life.
Recently, video surfaced of Jude Law singing 'Johnny B. Goode' at a bar in Carlsbad. Elijah Wood jammed to the Black Eyed Peas on stage at Fantastic Fest, and FunnyorDie's "Celebrity Karaoke" series, which began with Jewel, is getting picked up for television.
We've culled the Internet for the best of celebrity karaoke (via natural impulse, not from a televised show!). We found some actors, some singers, and some other notables -- and we have to say, our ears are loving it.
The RZA, Elijah Wood, Nacho Vigalondo, Eugenio Mira and Tim League sing 'I Got A Feeling'
Kelly Clarkson sings 'Sweet Child O' Mine'
Kelly Clarkson sings 'Ice, Ice Baby'
Joseph Gordon-Levitt sings 'Natural Woman'
Joseph Gordon-Levitt sings 'Bad Romance'
John Krasinski sings 'Hero'
Rod Blagojevich sings 'Treat Me Nice'
Rupert Grint and Oliver Phelps sing 'Fight For Your Right'
Rupert Grint sings 'I Got You Babe'
12-Year-Old Angelina Jolie (middle) sings 'Stand By Me'
Jack Black sings 'War Pigs'
Jewel sings her own songs!