London Irish have announced the signing of back-row forward Tom Guest from their Aviva Premiership rivals Harlequins.
Guest, 29, has agreed a two-year deal and he will move to Irish at the end of this season.
A club academy product, Guest has made more than 200 first team appearances for Quins and was part of their 2012 Premiership title-winning squad.
He also helped England Saxons win the Churchill Cup four years previously and has represented England Sevens.
"Tom is a title-winning Premiership player with a wealth of experience who has bought into what we want to achieve at this club," Irish rugby director Brian Smith said.
Guest said he is looking forward to "a new challenge" with Irish, and he will depart Quins after making a considerable impact at the Twickenham Stoop.
Quins rugby director Conor O'Shea said: "Tom has been one of Harlequins' great servants, having recently celebrated his 200th game.
"We would love to have kept Tom for his entire career, but the nature of managing a squad within the imposed salary cap regulations involves both accounting for the players you already have and developing personnel within each position."