'Bey' will sing some songs on a stage twice, once on August 17 and then again on the 18, in what's being billed as her only festival appearance of 2013.
The other headliner is, of course, Kings Of Leon.
Other acts added to the line-up include Emeli Sandé, Calvin Harris, Jessie J, Olly Murs, Paloma Faith, Rita Ora, Labrinth, Ellie Goulding, Jessie Ware, James Arthur, Little Mix and Travis (!).
Tickets go on sale on Friday morning at 9am and there's more information on all that here.