Harlequins fly-half Ben Botica will join Montpellier at the end of the season on a two-year deal and Tito Tebaldi is also set to leave the Stoop after agreeing a switch to Benetton Treviso.
New Zealander Botica has scored 544 points in 93 appearances for Quins since arriving at the Premiership side from Perigueux, but the 26-year-old has now opted to join Top 14 high-flyers Montpellier as a replacement for the Toulon-bound Francois Trinh-Duc.
Botica said: "It was a very hard decision for me to leave Harlequins. The last four years, in terms of my development as a player, have been priceless. Being around such a great group, in playing ability and as people, is something you can't buy.
"Had it not been for Conor [Quins director of rugby O'Shea] calling me up four years ago in New Zealand, I don't know where I would be with my rugby career, so I'm truly grateful to the club for the opportunity they gave me having not seen too much of me.
"It's beginning to hit home how much I will miss this club and the people associated with it. I've been given a new and exciting challenge in France with Montpellier, but my immediate focus is to help Harlequins finish top six and win European silverware."
Scrum-half Tebaldi, who joined Quins from Ospreys in December 2014, will return to Italy with Pro12 side Treviso after making only eight appearances for the London club this season.