Tomkins will wear the No. 14 shirt for the Barbarians in a one off game which will see the 22-year-old switch codes from league to union.
His teams mates will include flying union winger, Bryan Habana, as well as former England rugby union fly-half Danny Cipriani. The team will be captained by ex-Springboks lock Victor Matfield.
Barbarians’ commercial director Mike Burton said: “We are delighted that Sam, with the support of the coaches and management at Wigan, has accepted this opportunity to play in such a high-profile union match.
“In recent years the likes of Mat Rogers, Lote Tuqiri, Wendell Sailor and, a few months ago, Willie Mason, have all made a mark when playing for us on the big stage. We are confident that Sam will be equal to the challenge this week.”
Ian Lenagan, chairman and owner of the Warriors said: “The Wigan club and Sam are very pleased to accept the Barbarians’ invitation.
“Sam is an exceptional player in either code of rugby and his selection shows the growing mutual respect between the codes of rugby league and rugby union in England.
“It’s a great opportunity for Sam to experience the Twickenham atmosphere and showcase his talents on another major stage.”
Tomkins recently said he was committed to rugby league in wake of his brothers recent shock code switch to join Saracens.