Peel (Scarlets), Sweeney (Dragons), Yapp (Blues) and Thomas (Ospreys) are representing each of the four regional sides in Wales as well as the nation.
And WRU general manager Steve Lewis would like to thank each of the regional sides in particular for ensuring that the players are available.
"This game has our full support, but also the support of the Regions, without whose agreement we would not have been able to release the players," said Lewis.
"The WRU is only too happy to help with this match, not only is it for a good cause, a human disaster that touched us all but it gives these players the opportunity to play with and against some of the best players in the world.
"John Yapp, who has already put in some hugely encouraging performances so far this season, will be packing down in the front row with the likes of Pieter de Villiers, Raphael Ibanez and Gordon Bulloch and against the might of the southern hemisphere while Dwayne Peel will have the change to pit himself against George Gregan, arguably the best scrum half in the world.
"Jonathan Thomas will have an almighty back row battle on his hands when he comes up against the likes of Schalk Burger and Toutai Kefu while Ceri Sweeney will be fighting it out with David Humphreys to play against New Zealand great Andrew Mehrtens.
"Rugby is a sport that unites, both on and off the field and what better way of helping the victims and their families than through playing rugby?"
The proceeds for the match will go to the IRB's humanitarian partner, the United Nations' World Food Programme (WFP) to support the vital rebuilding work being carried out in the region devastated by the Tsunami on 26 December 2004.
North Squad : Lawrence Dallaglio, Ben Cohen (England), Aurelien Rougerie, Damien Traille, Fabien Pelous, Raphael Ibanez, Pieter de Villiers (France), Brian O'Driscoll (captain), Paul O'Connell, David Humphreys (Ireland), Chris Paterson, Chris Cusiter, Gordon Bullock, Simon Taylor (Scotland), Andrea Lo Cicero, Marco Bortolami, Sergio Parisse (Italy), Dwayne Peel, Ceri Sweeney, Jonathan Thomas, John Yapp (Wales).
South XV: Chris Latham (AUS); Rupeni Caucaunibuca (FJI) Jacque Fourie (SA) Tana Umaga (NZ), Sireli Bobo (FJI); Andrew Mehrtens (NZ) George Gregan (AUS, capt); Carl Hoeft (NZ), John Smit (SA), Kobus Visagie (SA), Ifereimi Rawaqa (FJI), Victor Matfield (SA), Schalk Burger (SA), Phil Waugh (AUS), Toutai Kefu (AUS).
Reserves: Bruce Reihana (NZ), Brian Lima (SAM), Ephraim Taukafa (TON), Opeta Palepoi (Sam), Semo Sititi (SAM), Moses Rauluni (FJI), one player to be announced.