Gladys Knight revisits one of her older hits with her backup group, the Pips, except that the Pips ain't with her this time.
Instead, actors Ben Stiller, Robert Downey, Jr., & Jack Black make up a new ensemble of Pips. Now, we know two of those guys can sing, and apparently, they can also groove. You can also figure out which one is the most challenged in this clip.
Edit: 4/17/14: Thanks to correspondent Magicdog for noting that this comes from the '08 season finale of American Idol.