They join acts including Alexandra Burke and Tulisa Contostavlos, who were announced in April.
Conor Maynard, Rita Ora and Wretch 32 are some of the other stars playing at Weston-super-Mare on July 1.
The first performers announced were Little Mix, Dappy, Labrinth, Professor Green, Rizzle Kicks and Cover Drive, back in March.
T4 on the Beach is celebrating its tenth anniversary this year. To get tickets for the event, go to the Channel 4 website.
Watch highlights from ten years of T4 on the Beach below: