How about we take a little stroll through one of my favorite movies, An American in Paris, and take a look at one of its more interesting characters, Oscar Levant. First, one of my favorite dance numbers from any musical:

(I Got Rhythm is terrific, too) Gene Kelly is one guy who could dance and still be a man's man if you know what I mean. My interest in the film led me to look into one of the film's supporting cast, Oscar Levant. Here's Levant's big scene showing off his musical virtuosity:

Levant was quite a character. A raconteur and wit, he was haunted by his genius and felled by a flawed character. A life of prescription drug addiction and occasional forced institutionalization is recounted in his no-holds-barred autobiography, The Memoirs of an Amnesiac. One of his most oft-quoted quips: "There's a fine line between genius and insanity. I have erased this line."

Here is audio of Levant playing Chopin. Those more versed in such things can be the judge of his talent. He had a live television show -- until his unscripted remark, "Now that Marilyn Monroe is kosher, Arthur Miller can eat her," became one of the things (as well as his substance abuse IIRC) that led to the show's change to tape for broadcast. According to the remarks at YouTube, this badly recorded 1958 episode with guest Fred Astaire is the only remaining record:

Modern viewers will marvel at Levant's chain smoking ways, particular as Astaire sings right next to him (click through for parts two and three of the episode). Levant is clearly not all there, and Astaire hangs right in with him in good humor.