Jim Hamilton is to leave Gloucester for France at the end of the season.
The club captain has agreed a deal with an unnamed Top 14 club and will quit Kingsholm with a year left on his contract.
Gloucester will receive compensation for their Scotland second row, whose imminent departure is the latest example of French rugby's financial clout.
Director of rugby Nigel Davies said: "It's a fact of life in the modern game that the French sides currently have much bigger playing budgets than their English counterparts.
"Jim is a fine player, an experienced international and has been a big part of what we've achieved so far this season at Gloucester Rugby.
"However, the offer is significant, and it would be wrong of us to try and stand in Jim's way. It's a massive opportunity for him. We don't want to lose him and he's aware of that. We're not the first team to lose a player this way, we won't be the last."
Hamilton, who joined Gloucester from Edinburgh in the summer of 2010, said: "The time I've spent at Gloucester has been the best of my career.
"However, the offer from France is simply the opportunity of a lifetime and one that I just couldn't ignore. It's a great move for myself and for my family. I hope that everyone will understand that."
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