The answer in Nicol Williamson as Merlin in Excalibur.
Did anybody mention Madeline Kahn in Blazing Saddles?. Her song and dance routine was a killer.
This isn’t quite stealing the movie, but in Dick Tracy, Madonna’s singing was so mediocre, that Mandy Patinkin, as her piano player, outsang her with only one line of song.
Have you ever seen Destry Rides Again? Kahn NAILED the parody of Marlena Dietrich.
Yep. especially when you think about what “stealing the movie” really means. It’s not just which supporting or otherwise minor performance was the best or most memorable, it’s when that supporting performance is so fantastic that the rest of the movie virtually disappears, particularly the star, who, in case anyone forgot, was Kurt Russell.
Val Kilmer IS Tombstone.
And running a second so close even a high speed camera isnt’ quite sure is Heath Ledger as the Joker.
These two performances are the complete definition of movie-stealing.
YES.
Favorite line: “…that awful Pooka.”
I’d like to thank everyone in this thread. I downloaded and watched Tombstone last night for the first time.
Gratitude!
Get back to us when you’ve watched it for the fifth or sixth time. 
(Seriously, though – welcome to the club!)
Jack Black in ‘High Fidelity’.
Amy Adams in ‘Doubt’.
Mark Wahlberg in ‘The Departed’.
Thought I’d have more; guess that’s all I got.
mmm
Little things are so cool in that movie, for example, if you watch closely, in the seen right after the marshall is shot,
Cowboy: you’re so drunk you’re probably seeing double.
Holliday: that’s ok, I’ve got 2 guns, 1 for each of you
If you watch closely, he spins the pistols in opposite directions, too fuckin’ cool.
Ad now you agree that Kilmer’s is the definitive movie-stealing performance, of course.
I know this is a difficult claim to support, but I’ve read that even serious students of frontier history agree that Kilmer nailed it.
Okay, I’ll go against the tide here. I like Kilmer’s Doc very much, and he certainly commanded certain scenes, but I absolutely disagree with this analysis.
First, Doc is in no sense a supporting character. He’s the number-two figure in the entire story after Wyatt. Here I mean the actual true story, which I’ve studied along with all of its portrayals in film. All accounts and versions of the story assign immense importance to Holliday. Tombstone itself gives shared top billing to Russell and Kilmer.
Second, the rest of Tombstone hardly “disappears” for me. “Skin that smoke wagon”? Ringo? The Ringo-Doc rivalry couldn’t work without great performances in both roles. And besides acting performances, a lot of this film’s value is in the meticulously researched sets and costumes, and Cosmatos’ direction. Obviously not having Kilmer in the role would be a shame, but it would still be the preeminent Wyatt Earp movie without him.
Owen Wilson in Meet the Parents? He maybe didn’t steal it from Stiller and DeNiro but he certainly burst onto the scene.
I don’t know if its THAT good. I’m sure I’ll watch it again, but it doesn’t quite rank up there for me as worthy of five or six viewings.
I remember reading somewhere that even though Cosmatos was billed as the director, Kurt Russell actually directed the movie.
Also, a funny quote that someone had on Facebook was, “Smoke that skin wagon.” The girl was embarrassed when someone pointed out the mistake.
I am going to throw the PotC debate a spin and say that Bloom, Knightly and Depp were the movie, but how did lot security not notice Lee Arenberg and Mackenzie Cook carrying that whole franchise out to their car. Pintel and Ragetti made those movies.
We’re your huckleberries.
Walter Brennan in “Rio Bravo” – no mean feat, given the strong performances by Deano and Duke Wayne.
Robert Duvall in “True Grit”
Someone may have already mentioned these:
Russell Brand saved Forgetting Sarah Marshall. If not for him it would have been a terrible movie.
Bronson Pinchot stole a big chunk of Beverly Hills Cop. In fact, another actor’s lines were cut from the scene because the director thought Pinchot was so funny. Then they brought him back for the sequel, which must have required some plot gymnastics.
Rupert Everett OWNED My Best Friend’s Wedding, although Cameron Diaz did a good job with a nothing role.