Terrence Hepetema has agreed to join Grenoble from the 2022/23 season.
The centre, who has made 52 appearances for London Irish to date, will leave the Exiles at the conclusion of the current campaign.
“Terrence has served the Club well since he joined us in 2018, helping us gain promotion from the Championship, as well as the last two seasons,” said Declan Kidney, Director of Rugby.
“We wish him and his family well as he continues his rugby playing journey.”
Hepetema added: “This is a good opportunity for me and my family at this stage of my career and one I am excited about.
“I’ve really enjoyed my time at London Irish and it goes without saying that I will give my all between now and the end of the season.”