The singer replaces US folk singer Lissie, who will no longer appear at this year's event.
V Festival takes place on the weekend of August 18 and 19 with alternating lineups at Hylands Park and Weston Park.
This year's event is headlined by The Stone Roses and The Killers.
Other artists on the bill include Contostavlos's N-Dubz bandmate Dappy, Snow Patrol, Noel Gallagher's High Flying Birds, Rita Ora, Nicki Minaj, David Guetta, Tinie Tempah, Wretch 32 and Ed Sheeran.
Contostavlos has said that she is not sure if she will perform her new solo material on The X Factor UK.
Watch Tulisa Contostavlos's video for 'Young' below: