On Friday, Lil Jon — who acted as musical director of the performance and appearing for "Turn Down for What" and "Yeah!" — opened up about the "hardest part" of putting together Usher's set on ...

where he was the show's musical director and performed a part of "Turn Down for What" before transitioning into "Yeah!" with Usher and Ludacris. "It was quite a process to do," Lil Jon said.