Wales full-back Liam Williams will rejoin Scarlets from Saracens at the end of the season.
The British and Irish Lions player left the Welsh region for the European champions in 2017.
He is out of contract with the English club at the end of this season and, despite interest from Ospreys, has opted for a return to Llanelli.
Williams is Saracens' first major departure since they were heavily punished for salary cap breaches.
The English Premiership champions were deducted 35 points and fined £5.36m in November for breaking rules over three seasons.
Saracens will not be contesting their punishment, while Premiership Rugby has announced a "comprehensive review" of its salary cap regulations.
"I've thoroughly enjoyed my time at Saracens over the past three seasons," said Williams.
"The environment has undoubtedly developed me as a player and a person. I am grateful for the support I've had from the players, management and supporters during this time.
"The opportunity to return home to the Scarlets was too good to turn down and I am incredibly excited about the future."
Signing a player of Williams' calibre is a significant coup for Scarlets, whose potent backline already boasts several Wales internationals such as Leigh Halfpenny, Jonathan Davies, Hadleigh Parkes, Rhys Patchell and Gareth Davies.
The 28-year-old is currently recovering from surgery to an ankle injury he sustained during the World Cup, which could make him a doubt for Wales' Six Nations campaign, which starts on 1 February at home to Italy.
However, his Scarlets return will be welcomed by new Wales head coach Wayne Pivac.
Once he is back with the region, where Williams formerly worked with the New Zealander, the full-back will be available for every Wales match and training session, which would not have been the case had he stayed in England.