Wales flanker Dan Lydiate has joined Ospreys on a national dual contract between the Welsh Rugby Union (WRU) and the region.
Lydiate reached an agreement to leave Racing Metro after just 17 months in France.
The 26-year-old moved to Racing in June 2013, but struggled to hold down a first-team place.
"I enjoyed my time with Racing Metro but this is the right move for me," Lydiate said.
Lydiate has been capped 41 times by Wales and featured in all three Tests for the British and Irish Lions in the victorious 2013 tour of Australia.
In November, it was announced the back row forward was among 12 players to be offered dual contracts by the WRU.
The list has been drawn up by Wales coach Warren Gatland, who has worked closely with the Ospreys, Newport Gwent Dragons, Cardiff Blues and Scarlets.
"This is an important step forward for Welsh rugby and [we] will reap rewards in playing standards over the long term," Gatland said.
"Any player on a national dual contract will remain in Wales with a region where their development and welfare can be monitored by me and my national squad coaches and conditioners."
Lydiate, who starts training with the Swansea-based region this week, is likely to make his Ospreys debut against Ulster in the Pro12 on 20 December, but will not be eligible for the group stages of the European Champions Cup.
He says he is "delighted" to become only the second Welsh player to sign a dual contract, following Wales captain Sam Warburton.
"Having a national dual contract gives me the certainty I need for my future and I will now be able to concentrate 100% on my rugby," Lydiate said.
"I am looking forward to doing my best for the Ospreys, while I aim to win selection for Wales."
The creation of dual contracts was part of a £60m deal between the WRU and regions over funding and governance of the professional game in Wales.
The deal states players returning to Wales on dual contracts must first be offered to their region of origin, before being available to the other three if no agreement can be reached.
Lydiate played for the Newport Gwent Dragons between 2006 and 2013, but has chosen to join Ospreys "principally for family reasons".
"This is a landmark day for Welsh rugby and I am grateful to all involved for the level of cooperation this signifies," WRU chief executive Roger Lewis said.
"National dual contracts will help us keep international class talent here in Wales available for regional rugby and for international selection.
"The WRU has been actively attempting to introduce national dual contracts for some two-and-a-half years, so securing Dan as a national dual contract player is a significant step forward."
Ospreys chief executive Andrew Hore is happy with the deal.
"We base our recruitment on selecting people with the right character," Hore said.
"Dan matches those requirements and we look forward to working with him."