Bristol have confirmed the signing of former Wales captain Ryan Jones on a two-year contract.
Jones, 33, will move to the Championship promotion contenders once this season's Pro12 commitments with the Ospreys are over.
It represents a significant coup for Bristol, with back-row forward Jones having won 75 caps, captained his country more times than any other player and been part of three Grand Slam-winning sides.
"This has definitely been the toughest decision I've ever had to make, but it's one that I'm making for my family," said Jones.
"I've had a fantastic 10 years with the Ospreys and will leave with so many good memories to treasure.
"I'm immensely proud of everything we've achieved as a group, with five trophies to look back on, and that success has enabled me to enjoy significant success at international level as well.
"It's truly been a fantastic journey."
Jones hopes a fresh challenge will help prolong his international career.
"The vision of Bristol, the passionate fanbase, and the direction that the club is going is a huge attraction for me," he said.
"I want to test myself at the highest level in the English game, and I'm determined to achieve that as a Bristol Rugby player."
Bristol director of rugby Andy Robinson added: "Ryan's arrival indicates the ambition that Bristol Rugby has and the quality of players we are capable of attracting.
"To captain your country a record number of times and to play for the British and Irish Lions is no mean feat - what Ryan has achieved in his career so far is remarkable.
"His influence - on and off the field - will be significant for us, both during the play-offs this season and next. Ryan is hungry to help Bristol move forward and drive our progress."
Bristol currently lead the Greene King IPA Championship by three points from London Welsh, with the top four clubs qualifying for play-offs in May in pursuit of potential promotion to the Aviva Premiership.