Kilmer also warbled a bit in The Doors.
The excellent Talking Heads movie True Stories featured songs by the cast (including John Goodman) and two different soundtrack albums - one featuring the cast and one entirely by Talking Heads.
Don’t forget Hoagy Carmichael in The Best Years of Our Lives. Anybody know if that was actually Harold Russell playing “Chopsticks” with Hoagy, or was it an overdub?
And, of course, there’s Huey Lewis, Gwyneth Paltrow, Paul Giamatti, and Maria Bello in Duets.
Jonathan Rhys-Meyer does some, but not all, of his own singing in the same movie.
Ewan McGregor also sings in Emma (in fact, he got the part in Velvet Goldmine partially because of this), and of course the already-mentioned Moulin Rouge.
Jude Law did his own horn playing in The Talented Mr. Ripley. Interestingly, the character in the novel is a painter, not a musician. Maybe Jude Law can’t paint. 
Holly Hunter played the piano in the aptly named The Piano.
Aaargh! Somehow I missed Brondicon’s post for Duets.
Sorry, Brondicon.
My understanding is the cast album was never released, just the version with the band (supposedly against Byrne’s wishes). I’ve never seen the album, though it’d be interesting to hear…
There are, of course, all the great jazz musicians in Robert Altman’s Kansas City who provide all the musical interludes, and while we’re talking about Altman, all the actors performed their own songs in Nashville as well.
Also, don’t forget the Woody Allen movie Everyone Says I Love You where the entire cast–Woody, Julia Roberts, Edward Norton, Tim Roth, etc.–perform their own songs (except for Drew Barrymore). Diane Keaton also sang in Annie Hall.
Gary Oldman did the singing himself in Sid & Nancy.
ArchiveGuy - I think you might be right. I’d heard there were two version, but only owned the non-cast one. The IMDB agrees with your version though.
I’m going off memory here, and it’s been 16 years, but I’m positive I saw the True Stories cast soundtrack album in a store on vinyl. I could be mistaking it for a 12 inch single of Wild Wild Life for all I know, but memory is telling me it was the cast album.
I seem to recall that the actors in Nashville not only performed, but wrote their own songs, and that Keith Carradine got an Oscar nomination for his song “I’m Easy”.
Didn’t Tom Hulce do most of his own playing in Amadeus? It’s a mystery to me why he hasn’t had a bigger movie career.
Darn it, ArchiveGuy beat me to Nashville before I got a chance to mention it. I do believe that the actors involved not only performed those songs, but co-wrote them as well. I know that Henry Gibson’s turn as super-patriot Haven Hamilton is such spot-on satire that it’s reason enough for anyone to see the movie.
I forgot a particularly notorious example: Sylvester Stallone doing his own singing as an aspiring C&W singer, alongside Dolly Parton, in Rhinestone. Oh, is he bad.
In “The Night the Lights went out with Georgia” Kristy McNichol sings for herself.
I believe Lisa Bonet sang in High Fidelity.
I thought that Clint Eastwood really played the piano in In the Line of Fire but a check of the IMDB trivia page for the film didn’t mention it.
I read in a review that Jane Horrocks did all her own singing in Little Voice. Is this true?
According to the back of the video box, it is.
Also, not only was Richard Gere doing his own piano work in Pretty Woman, he also did all his own trumpet work in The Cotton Club.
As for Dudley Moore, he also played his own piano in Arthur, but did not play the violin in Unfaithfully Yours. And he probably wasn’t really conducting orchestras in Unfaithfully Yours and Foul Play, although he probably could have.
Also, I don’t have my copy of The Fabulous Baker Boys handy, but IIRC, Jeff Bridges played his own piano, but Beau did not.
I could have that wrong.
I understand that Tim Blake Nelson did the actual vocals for “In the Jailhouse Now,” at the end of O Brother, Where Art Thou, although all of the rest of the singing was dubbed. Also, the Tommy Johnson character was played by professional blues guitarist Chris Thomas King.
He won the Oscar.
Cameron Diaz sings on song on the Vanilla Sky soundtrack, as her character in that movie.
And most (all?) of the voice actors did their own singing for the South Park movie. (And songwriting, as well, in a couple of cases.)
Ranchoth
(Does it sort of concern anyone else that Trey Parker and Matt Stone can put “Acadamy Award nominated Composer” on their resumes?)
Antonio Banderas sings the opening song in Desperado.
Have we forgotten all Monty Python movies? Or Mel Brooks films? All of those had at least one person singing something. Usually, not very well in the Mel Brooks films, but it was singing nonetheless. Technically, anyway.
Oh, and John Carpenter does the music for all his movies. Who can forget the memorable theme to “Big Trouble in Little China”?