Joe Greenwood will give Wigan a mid-season boost after completing his move to the club.
He has signed a three-and-a-half year deal after securing a release from the Gold Coast Titans.
His capture, announced tonight, came hours after Joel Tomkins' departure to Hull KR.
But the Warriors were already in talks with Greenwood before then, ultimately as a replacement for John Bateman next season if he completes a move to the NRL, as expected.
Executive director Kris Radlinski said: "We have been engaged in discussions with Joe and his representatives for a good few weeks now but last week, negotiations progressed quickly and we are now in a position to announce him signing for Wigan.
“At 6 feet 3 inches and weighing 110kgs he is a big athlete who always caused us problems when he played for St Helens and I’m very excited to see him in a Wigan shirt.
"Joe is a great addition to our squad and we look forward to welcoming him here."
Greenwood is expected to arrive at the club later this month.
He made his name at St Helens, making 77 appearances, before moving to the NRL where he played 22 games for the Titans last year.
But new coach Garth Brennan did not see the former Saddleworth junior in his plans.
Greenwood, 25, initially vowed to stay and fight for his place but has been unable force his way into the mix.
Brother of ex-Warriors prop James, Greenwood said: "I am really pleased to have signed a long-term deal for Wigan and to move on to the next chapter in my career.
"Wigan is a massive club and speaking a few times to Ian Lenagan and Kris Radlinski I felt it was the right decision to make and a great opportunity for me. I can’t wait to get over there and get stuck into the business end of the season.”
Wigan have already secured the signing of Zak Hardaker for next season.