Mariah Carey, Jamie Foxx Help Celebrate Apollo Theater Anniversary

ET was exclusively backstage at the 75th anniversary celebration of the Apollo Theater in New York on Monday night -- where Mariah Carey, Jamie Foxx, Bill Cosby, Quincy Jones, Patti LaBelle, and others came out for the big night!

The theater celebrated the event, hosted by former "It's Showtime at the Apollo" host Steve Harvey, with a gala benefit tribute concert and awards ceremony, in which Quincy Jones and Patti LaBelle were inducted into the Apollo Legends Hall of Fame. Mariah Carey presented Patti with her Hall of Fame award.

Watch the video to see ET's interviews with the night's biggest stars -- plus, see exclusive backstage footage from the bash!