Fiji wing Nemani Nadolo will join the Barbarians for a return to Twickenham after the conclusion of the Rugby World Cup.
The 27-year-old, a try scorer against England in the World Cup's opening match, is one of the stars of the tournament so far.
And he will make his debut for the famous invitation club in big games against Argentina and Gloucester in November.
The Barbarians, coached by Australia’s Michael Cheika, take on Gloucester at Kingsholm on November 17 before facing Argentina on November 21.
Cheika will have some of the world’s biggest names in his squad with the likes of South Africa’s Jean De Villiers, Patrick Lambie, Victor Matfield and Tendai Mtawarira already confirmed.
There are more signings to come and players from the New Zealand and Australia World Cup squads among them.
The Barbarians, who beat Samoa 27-24 at the former Olympic Stadium last month, were founded 125 years ago and the Killik Cup match against Argentina is the centrepiece of the anniversary celebration.
“The Barbarians do a wonderful job of bringing different nations and talent together to celebrate rugby on the world stage,” said Cheika.