Danny Cipriani and Stephen Jones have won Barbarians call-ups for the first time for the November Test with Australia at Twickenham.
Wales number 10 Jones and England international Cipriani, overlooked for Martin Johnson's World Cup squad, will join a stellar cast for the match.
Welsh pair Jamie Roberts and Ryan Jones join South Africans Victor Matfield and Bakkies Botha in the Baa-Baas squad.
Ex-Wallabies skipper Stirling Mortlock will play against his old team-mates.
New Zealand centre Sonny Bill Williams has joined countryman Keven Mealamu, the All Blacks hooker, in accepting an invitation from the Barbarians to play the newly crowned Tri-Nations champions in London on Saturday, 26 November.
Matfield led the Barbarians to victory over New Zealand in 2009, and the World Cup winner will be joined in the second row by Springbok and Blue Bulls colleague Botha.
"My sights are firmly set on a successful Rugby World Cup campaign with South Africa in New Zealand," said Matfield.
"But after that there is no better way to sign off in the northern hemisphere than another game for the Barbarians against international opposition at Twickenham."
British and Irish Lions centre Roberts will be joined in a strong Baa-Baas back-line by Jones, Cipriani, Williams and Mortlock.