GRAMMYS BOOK GAGA; IS BIEBER NEXT?

Lady Gaga is the latest last-minute confirmation for Sunday's Grammy Awards. Meanwhile, inside sources say Justin Bieber will definitely be performing on the Grammys as well.

Biebs has a show the night before (4/2) at PPG Paints Arena in Pittsburgh, but sources tell us he will absolutely make the trip to Vegas. He's up for eight Grammys, including Record, Song (both for "Peaches") and Album of the Year (Justice). We're told that he will perform "Peaches" on the show. Stay tuned for updates.