When you think of Singin' in the Rain, chances are Gene Kelly is the man who immediately comes to mind. And for good reason, too, they make bobble heads of him, for God's sake. But when you watch Singin' in the Rain and focus entirely on the leading man, you're missing out on an incredible performance by a vaudeville veteran who could match Gene Kelly step for step and had a killer sense of humor. Almost every single one of his one-liners in this film lands perfectly, and he's a wonderful counterbalance to the more earnest and self-centered Don Lockwood. He plays Cosmo Brown, a talented pianist who plays mood music on the sets of Lockwood's films, and he's been best friends with Don since they were both lower-class urchins using their skills to fend off poverty. Throughout the entire film, his main job is to bolster Don Lockwood, whenever he's feeling depressed or discouraged, with his constant optimism and tongue in cheek humor. But seriously, who would you want as your best friend, the famous guy who's always running around bemoaning his troubles, or the man who responds to adversity by saying, "At last, I can start suffering and write that symphony!"