Ospreys front-rower Cai Griffiths has agreed terms to move to London Irish in the summer.
The 28-year-old has won the domestic title three times while at the Ospreys and racked up more than 100 appearances.
However the powerful scrummager, who will be a direct replacement for Faan Rautenbach, has now opted to make the switch to the Exiles.
Griffiths said: "Joining London Irish offers me the chance to test myself in a gruelling Aviva Premiership competition week in, week out.
"It is a challenge I am certainly looking forward to and one I am relishing.
"I have enjoyed nine fantastic years at the Ospreys and would like to thank the players and coaching staff for all their help during my time there."