Former Sydney Roosters centre Setaimata Sa will cross codes and join London Irish at the end of the season.
The 24-year-old, who has played in the centres and back-row for Super League club Catalan Dragons, has agreed a three-year deal with the Exiles.
Sa has made 39 appearances for the Dragons, having moved to France in 2009 after a previous spell at the Roosters, while he has been capped by both New Zealand and Samoa.
Irish director of rugby Brian Smith said: "There's no doubt about it, Setaimata is an exciting and wonderfully skilful player and we're delighted that he will be joining the squad next season.
"I have followed his NRL and Super League career very closely and he was coached at the Roosters by my good friend and current New South Wales State of Origin coach, Ricky Stuart.
"We've needed to replace Seilala Mapusua in midfield for some time now and Sa fits the bill perfectly.
"He is an outstanding defender and a powerful runner with great physical and technical abilities.
"Still just 24 years old he already brings with him a wealth of international and top-flight rugby experience, as well as winning a rugby league World Cup for New Zealand. We think he is going to take the Aviva Premiership by storm."