The Sugababes singer will take to the stage with Tinchy Stryder to perform their new single 'Never Leave You' at the day-long music festival in Weston-super-Mare on July 19.
Previous acts confirmed include Dizzee Rascal, The Saturdays, Gossip, Calvin Harris, Alesha Dixon, Basement Jaxx, Will Young and JLS.
T4 presenter Miquita Oliver confirmed that further surprise guests are yet to be confirmed.
"I can't believe there's only two weeks to go! It really is the party of the summer. With the new artists we're announcing and the surprise guests we have up our sleeves, the lineup just gets better and better," she said.
"I can't wait to get down on the beach now and get the beach rocking! Let's just hope the sun stays out when July 19 comes round!"