Ireland scrum-half Tomas O'Leary will leave Munster to join London Irish from next season after signing a three-year deal with the Premiership club.
The half-back, 28, has been capped 24 times by his country, most recently against England last Saturday.
O'Leary said: "I have been lucky enough to be part of winning teams at both Munster and Ireland and hope for even more success as a London Irish player."
He was a member of Ireland's Grand Slam winning side of 2009.
It had originally been speculated that the Cork-born player, who was part of Munster's Heineken Cup winning team of 2008 but has recently fallen down the pecking order internationally and for his province, would move to France.
London Irish director of rugby Brian Smith told
the club's website:
"It is great to be announcing this week, just ahead of our St Patrick's game, that a current Irish international will be joining us for next season.
"Tomas will be a fantastic addition to our squad. He is a proven scrum-half who has represented his country at the highest level. He will bring with him a wealth of experience and a winning mentality. We look forward to welcoming him to the club this summer."
O'Leary added: "Joining London Irish presents a new and exciting chapter in my career and one that I am really looking forward to.
"I am looking forward to working alongside Brian and the coaching team and testing myself in the Aviva Premiership and playing alongside a very talented squad at London Irish."