Canadian winger DTH van der Merwe will join the Scarlets next season
The club's leading try scorer will bring to an end a six-year spell in Glasgow when he moves to the Welsh region in the summer.
The 28-year-old has scored 39 tries in 90 appearances for the Warriors and has 28 caps and nine tries for Canada.
DTH van der Merwe said: "I am extremely grateful to Glasgow Warriors for all that they have done for me since I joined back in 2009.
"I have had six great seasons at Glasgow but I feel that the time is right for me to face a new challenge.
"We have some big games coming up between now and the end of the season and after missing the second part of last season, including the final through injury, I'm hoping I can play my part this time around."
Glasgow Warriors head coach Gregor Townsend added: "DTH has been a great player for us over the last six years and has become the club's record try scorer.
"He has always given one hundred per cent and has played his part in the development of the club.
"We'll be sorry to see him go, but we wish him well when he leaves us in May."
Glasgow Warriors head into Saturday's Guinness PRO12 semi-final against Connacht without two of their key men after Alex Dunbar and Sila Puafisi were ruled out due to injury and suspension respectively.