CBS said T-Pain and Dwight Yoakam have also agreed to appear at the event, which will be broadcast live on the network Wednesday.
Added to the previously announced lineup of performers is French disc jockey and producer David Guetta.
The one-hour special will be taped at Club NOKIA in Los Angeles, with rapper and actor LL Cool J serving as host, CBS said.
'Happy' fan videos make Pharrell cry [VIDEO]
Pistorius testifies he didn't consciously pull trigger when he shot girlfriend