Los Angeles - Two-time Rugby World Cup winner, New Zealand's Ma'a Nonu, has signed with the San Diego Legion, Major League Rugby announced on Wednesday, giving the North American league its biggest star.

The 37-year-old All Blacks center, among Super Rugby's all-time try scorers, will join the 12-team North American league ahead of its third season that opens in February.

"I'm really grateful to be joining the San Diego Legion and to play in the MLR for the 2020 season," Nonu said.

"I'm looking forward to the challenge of the new season ahead with the team. My family and I are excited about the move to San Diego."

Nonu scored 155 points in 103 appearances for the All Blacks and has played since 2003 in Super Rugby for the Hurricanes, Blues and Highlanders with stints in France and Japan.

Landing the big-name star is a big boost for MLR, which began last year with seven clubs and grew to nine this year, most venues seating between 5 000-6 000 as the circuit tries to establish a foothold in the crowded American sports scene.

The Legion reached the playoffs in both MLR seasons, losing each time to the eventual champion Seattle Seawolves, 38-24 in the 2018 semi-finals and 26-23 in this year's championship match.

"Ma'a is a huge addition for us," said Legion coach Rob Hoadley.

"It's undeniable that he will have a major impact on the MLR this season. He is a world class player who has proven himself to be one of the greats of the game. His talent and leadership will be a perfect addition to the San Diego Legion."

Hoadley, this year's MLR Coach of the Year, says Nonu will join the Legion when pre-season training begins in December.