The ex-Scotland boss had known he was on his way out at the end of the season and had succeeded in getting the go-ahead to take over John McKee as Fiji coach.
However, rather than wait until the end of the Top 14 season to make the change, Montpellier have allowed Cotter to finish three months earlier than planned and he will be replaced by Philippe Saint-Andre, the former France coach.
Having previously coached Clermont to Top 14 glory, Cotter arrived back in the French league in 2017 and he finished his first season by guiding Montpellier to the final at Stade de France.
Following an amicable agreement negotiated with Mohed Altrad, Cotter is now clear to start preparing to lead Fiji whose first match under their new coach all be a July 4 meeting with Pacific Islands rivals Tonga.
WATCH: RugbyPass go behind the scenes at Montpellier to document the life and time of Fijian legend Nemani Nadolo
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