Roger Tuivasa-Sheck's return to rugby will be through the Blues in Super Rugby and Auckland in the national provincial competition.
New Zealand Rugby and the Blues confirmed on Saturday the captain of the Warriors rugby league side had signed a two-year contract through to the end of 2023.
The announcment also confirmed Tuivasa-Sheck would play NPC rugby for Auckland, joining the team "later this year" before starting with the Blues ahead of the 2022 Super Rugby season.
The NPC was scheduled to run from September 11 to November 27, with the Warriors NRL regular season campaign set to finish on September 9 and the Grand Final to be held on October 3.
"It has been a dream of mine for a long time to one day play rugby union again, to get this opportunity with New Zealand Rugby, the Blues and Auckland is exciting," the 27-year-old said.
"The timing feels right to do this now. That said, I have a big year ahead of me and will turn my attention to this opportunity later in the year."
Tuivasa-Sheck has become one of the biggest names in rugby league since embarking on a professional sports career in 2012, one year after playing for the New Zealand Secondary Schools rugby team alongside current All Blacks Patrick Tuipulotu, Ardie Savea, and Ngani Laumape.
The Samoan-born Aucklander joined the Warriors in 2016 and in 2018 was awarded the Dally-M Medal as the best player in the NRL.
New Zealand Rugby general manager of professional rugby and performance Chris Lendrum said Tuivasa-Sheck's return to rugby was a major coup.
"It's hugely exciting for everyone in rugby to have Roger back playing rugby union. He is a highly talented athlete who has achieved a huge amount in rugby league, but, equally, has proven himself as a leader on and off the field and an outstanding role model.
"Roger has some goals he wants to achieve in rugby, and we are thrilled to be able to give him the opportunity to chase those goals."
Tuivasa-Sheck spent his formative rugby years playing for the Otahuhu College 1st XV and went on to play for the Blues development squad as a teenager.
Blues chief executive Andrew Hore said they were thrilled to have his the rugby league start return to hi home Super Rugby club.
"His roots were in rugby and we know he will be an exceptional player. More importantly he is an outstanding leader who will embrace the links we are creating in the wider community.
"Roger will be a superb contributor to our club, and we hope his fans will follow him to Eden Park next season."