The second rower, 31, joins from Top 14 side Perpignan, who he joined in 2012 following a two-year spell with Bordeaux.

Before his move to France he spent four years with London Wasps, where he won the 2007 Heineken Cup and 2006 Powergen Cup.

Leo has played 34 Tests for his country and has featured in two World Cups in 2007 and 2011.

He made his first appearance in the Premiership in 2005, and Exiles director of rugby Brian Smith said: “Dan Leo is a seasoned campaigner and will be a huge asset to our squad next season. He knows what it takes to win big games and titles from his time at Wasps and has a wealth of Test match experience.

"He’s a big physical player comfortable at lock and across the back row. He adds further strength and depth to the pack and we’re delighted to have him on board.”

Leo added: “I’m excited to be moving back to England to join London Irish. I always enjoyed playing in the Premiership and I’m excited to go back to compete in that competition again.

"Irish are building nicely for the future it I’m looking forward to being part of it.”