London Irish have announced the signing of Setaimata Sa from Super League club Catalan Dragons on a three-year deal.
Sa, 24, can play as a line-breaking centre or a back-rower, and has scored 10 tries in 39 games for the Dragons.
"He's a wonderful player, he grew up in Christchurch so he's got a rugby background," Exiles director of rugby Brian Smith told BBC Berkshire.
"He's had three seasons in the NRL, three seasons in the Super League, he's the real deal, an offloading machine."
Smith added: "He's six feet three, 105 kilograms. 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."
Sa moved to Catalan Dragons from Sydney Roosters after a 2009 incident at a Sydney hotel.
He admitted charges of malicious damage, failing to leave a licensed premises and resisting arrest, but denied assaulting a female police officer. He agreed to be released from his contract with the Roosters.
Smith believes Sa can be an ideal replacement for Seilala Mapusua, who joined Kubota Spears in 2011.
He said: "He's an outstanding player. To say that he's going to fill Seilala's boots is a massive statement, but he's got the potential to do that. We think he is going to take the Aviva Premiership by storm.
"I've followed his career for the last six years. I spoke with his coach and he says that the Catalan Dragons are disappointed to lose him because they feel he has been their best player this season."
Sa, who has made three appearances for New Zealand's rugby league side and has five Samoa caps, is equally enthusiastic about the move.
"I'm really excited about joining London Irish. Returning to rugby union is something that I have been considering for a while, it has always been in my blood and testing my skills in the Aviva Premiership will be the ultimate challenge," he said.
"The style of rugby that the Exiles play and the family values of the club suit me and my family well.
"I'm looking forward to getting down to it in the summer and I hope to be able to make an immediate, positive impact."