Chelsea Handler [1]'s show Chelsea Lately came to a close on Tuesday night, and, of course, the funny lady made sure that her last night was a memorable one. Chelsea got a lot of help from her many A-list friends, including a special intervention from Jennifer Aniston [2], Mary McCormack, and Sandra Bullock [3] to address her party-girl ways. Of course, they weren't the only star guests, as Chelsea was joined by a massive group of celebrities at the end of the show for a hilarious sing-along. Watch Sandra, Jen, and Mary's intervention above, and check out the surprise musical number below.