Regan Grace has signed for Cardiff for the remainder of the 2024-25 season after completing his move from Bath.
The rugby league convert was targeted by Cardiff head coach Matt Sherratt who is without several injured players.
But the six-month Arms Park contract could be extended beyond this season.
"I've always been excited about Cardiff - it's a big, historical club and a lot of legends have played here," said Grace.
"Coming back to play on home soil has also always been something I have wanted to do, so to do that in the capital city is a great opportunity.
"I'm very much aware of all the dual-code legends who have played for, or come through, Cardiff, so to follow in those footsteps is pretty cool."
It is the latest twist in the 28-year-old's transition from rugby league to union following his surprise inclusion in Wales' tour Australia last summer.
The former St Helens star was only called into the Wales training squad as an injury replacement, but made his competitive union debut against Queensland Reds, scoring with almost his first touch.
Born in Port Talbot, Grace was part of the Ospreys academy, but switched to rugby league aged 17 before making a senior appearance.
A stellar rugby league career brought three Super League Grand Finals and the Challenge Cup title before returning to union in 2022.
But serious Achilles injuries delayed his debut, having initially joined Racing 92 in France before heading to Bath last year.
Since the Wales tour, Grace has made two cup appearances for Bath, but was keen for the move to gain regular game time.
"I just want to play, to be able to put together back-to-back matches, be consistent and keep learning," he said.
"You learn from playing and I'm looking forward to putting my hand up for selection."
Cardiff have once again turned to the Recreation Ground for help having signed Bath's Louie Hennessey on a short-term loan last month.
But unlike Hennessy, who is cup-tied for Europe, Grace is free to play in the forthcoming Challenge Cup ties against Perpignan and Connacht having left Bath.
Mason Grady, Harri Millard and Theo Cabango are all sidelined while Iwan Stephens is ruled out for the season with a knee injury.
Cabango is back in training after a serious hamstring problem and targeting a return later this month, but Wales back Grady is struggling to make the start of the Six Nations after fracturing an ankle.
Sherratt said: "Regan is a great addition in a position where we needed reinforcement.
"He is an incredibly exciting player. He impressed during the summer with Wales and we're excited to see what he can achieve as he continues his transition to union."