Ex-Wales and British and Irish Lions rugby union captain Gareth Thomas has joined Wrexham-based rugby league outfit Crusaders from Cardiff Blues.
The 35-year-old, the only player to win 100 caps for Wales, has agreed an 18-month deal with the Super League club.
"I'm really excited by the ambition of the Crusaders," said Thomas, adding that money was not a factor.
"Playing for someone of the experience and reputation of (coaches) Brian Noble and Iestyn Harris really excites me."
Thomas captained Wales to their first Grand Slam in 27 years in 2005, then took over the Lions leadership in New Zealand during the same year after original skipper Brian O'Driscoll was injured in the opening Test.
He has also played for Bridgend, Celtic Warriors and spent three years in France with Toulouse, where he won the 2005 Heineken Cup.
His skill levels are phenomenal and he brings a wealth of experience that you just can't buy
Crusaders coach Brian Noble
"This move was not about money but about a chance of a fresh challenge on the field and an opportunity to promote rugby in north Wales off the field," he added.
The capture of Thomas is also a huge public relations coup for Crusaders, with the high-profile Welshman an extremely popular and charismatic figure.
After a difficult first season - on and off the pitch - in the Super League last season, the club relocated to Wrexham in December and are hoping to connect with rugby league fans across north Wales.
Crusaders chairman Ian Roberts said: "This is a truly monumental day in the Crusaders' history.
"Getting a player of Gareth Thomas' stature and ability at the Racecourse is a major coup for us. We're building something special here at Wrexham. We want rugby league to succeed in north Wales."
Thomas revealed that a chat with fellow dual-code international Harris, who is assistant coach at Crusaders, persuaded him to seriously consider moving.
The pair played together for Wales during Harris' largely unsuccessful three-year stint in rugby union at the turn of the century.
Head coach Noble, who joined the club in October, admitted that a player of Thomas's calibre could only be good for Crusaders.
"I am delighted to have Gareth on board," said Noble, who has won two of his four Super League games in charge.
"As I've said in the past, I think Gareth Thomas is a fabulous player. He's an amazing athlete and I'm a huge fan of his talents. He's in fantastic shape and has clearly looked after himself over the years.
"He has all the attributes to succeed in rugby league, he's big and he's strong, has great footwork and he is not afraid to put in a shift in defence either.
My worry is that they will want to play him every game because they have only got a limited time with him
"His skill levels are phenomenal and he brings a wealth of experience that you just can't buy."
But former Wales captain Scott Quinnell, who switched to league at the age of 21 in 1994 before moving back to union, is not expecting Thomas to find the code-change easy.
"It's a very difficult move because he's been at the top of his game for so long in rugby union that to move across now you can only think it's for a fresh challenge for him," Quinnell told BBC Radio 5 live.
"At 35, it's a tough game, he will have to learn, he will have to take time to get used to playing rugby league because it's a totally different game.
"I couldn't imagine changing sports in my thirties, it's difficult to do when your are younger and have got time to learn."
He added: "My worry is that they will want to play him every game because they have only got a limited time with him.
"I think it's fantastic for Welsh sport to see the likes of Gareth trying new things but it's a difficult sport.
"The whole of the rugby union world will be watching him, as will rugby league."
Thomas has played his last game for Cardiff Blues, having been released with immediate effect. His first game in rugby league is likely to be a Super League fixture against Catalans Dragons on 19 March.
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