Britney Spears Dances to Song Featuring Ex Justin Timberlake | TMZ TV

In a video posted to Instagram, Brit was decked out in a skimpy outfit -- a see-through mini dress with underwear and heels -- while Timbaland's "Bounce" played loudly in the background.

Justin, Dr. Dre and Missy Elliott were also credited on the 2007 track.