The 11-man dance troupe, who beat Susan Boyle to the ITV1 show title on Saturday, will showcase their choreography and street dance skills at the festival on Sunday, July 5.
It will be one of the group's first live shows since winning the programme, which was watched by over 18 million viewers at the weekend.
Kanye West headlines the Sunday Wireless lineup, while Kelly Rowland, Flo Rida, Q-Tip, Tinchy Stryder and N-Dubz are also on the bill. Tickets are still available.
Diversity will also appear on the Britain's Got Talent live tour, which kicks off on June 12 at Birmingham's NIA.
> Click here to see Diversity at the winners press conference on Sunday