Here, we give you five things you didn't see on TV:
1. They Really Put J.T. to Work: With just seconds to go for the start of the show, it was Timberlake who walked onto the stage, grabbed a mic and announced, "Ladies and gentlemen, please take your seats!"
2. And They Always Have: Speaking of Mr. Timberlake, a Grammys producer gave him a shoutout before the show started to thank him when he "saved our ass when something unfortunate happened four years ago."
If you remember, it was the year Timberlake replaced Chris Brown at the last-minute for a performance of "Let's Stay Together" with Al Green, the year Brown was arrested and Rihanna went to the hospital.
3. Girls Rule: Lena Dunham was in the house tonight to support her boyfriend, fun. bassist Jack Antonoff. And she let him shine. She didn't do press and rushed into the auditorium just before the band's rain-soaked performance. She was one of the first to jump up to give them a standing ovation.
Later, Dunham and Antonoff were full of PDA, rubbing each other's back and stealing kisses.
4. J.Lo Is Flexible: Last minute change of plans for Jennifer Lopez and Pitbull. Their bit was originally supposed to have Pitbull take the stage wearing a shirt open to his navel with J. Lo cracking, "I guess you didn't get the memo." Instead it was Lopez, of course, showing the skin tonight in her slit-up-to-there Anthony Vaccarello dress.
5. It's Like Pretty Much Any Concert: Coming out of one dressing room backstage was the smell of the stuff that Justin Bieber promises to never smoke again. Kelly Clarkson got a whiff as she strolled by. "Whoa," she said, waving her hand in front of her nose.
Close by, Ellen DeGeneres sat on the floor strumming a guitar with a cup full of money.
What were your favorite moments from the show? Sound off in the comments!