Fielden was tipped to move to the NRL when his Bulls contract ended

The 26-year-old asked to be released from the remaining 18 months of his contract and will team up again with former Bulls coach Brian Noble.

"I have enjoyed my time at Bradford but I feel the time is right for me to leave," said Fielden.

"A new challenge and a much bigger salary made the decision easy for me."

Bulls chairman Peter Hood insisted that this was not the start of an era of Bradford being a selling club, and said no other players were for sale.

He is a world-class player and a fabulous addition to our squad Wigan coach Brian Noble

"When a player tells his head coach he no longer wants to play for the club, then we are dealing with an extraordinary situation in which the club has little option but to consider letting him go," he said.

"I am satisfied that the value extracted from the Wigan club is the best that could have been achieved."

Noble was clearly delighted to have signed such an experienced player.

"He is a world-class player and is a fabulous addition to our squad," said the Great Britain coach.

"This is a long-term signing, it's no quick fix. It's to establish ourselves on the right track."

This is a great opportunity for me and I jumped at the chance to work with Brian Noble once more Stuart Fielden

Fielden, who spent eight years at Bradford and played in the last five Super League Grand Finals, is regarded as one of the best forwards in the world and was tipped to move to the NRL.

"This is a great opportunity for me and I jumped at the chance to work with Brian Noble once more," he added.

"He has brought me through the ranks and his presence at Wigan played a bit part in my decision.

If Brian wants another player, we will go and get him Wigan owner Dave Whelan

"I've not come here believing the club are going down. I have come here to help them stay up and I believe they will stay up."

Wigan, who recently failed in two bids to sign Fielden's Bradford and Great Britain team-mate Paul Johnson, have also been linked with former player Terry Newton.

Wigan owner Dave Whelan hinted Fielden's signing may not be the last, saying: "This is what Wigan Rugby League Club is all about.

"We used to go out and buy the best players in rugby league. If Brian wants another player, we will go and get him."

FIVE LIVE VIEW It's good business by Bradford - Fielden has not been at his best so far and �450,000 for someone who will go for nothing in 18 months can only help BD Five Live: Have your say

Noble confirmed Fielden would make his debut against Warrington at the JJB Stadium on Friday night.

Fielden's arrival will be a huge morale boost for Wigan, who are four points adrift of Catalans Dragons at the foot of the Super League table.