Scotland lock Richie Gray will join Toulouse from French Top 14 rivals Castres at the end of the season.
The British and Irish Lion has agreed a four-year deal with the four-times European champions.
With his current deal due to expire next summer, Gray had received several offers from clubs around Europe.
Gray began his professional career with Glasgow Warriors and joined Castres from Sale Sharks in 2013.
The Rutherglen-born forward has 51 Scotland caps and has was selected for the Lions tour of Australia in 2013.
Castres finished 12th last season, one place above the relegation spots, in the French top flight, and presently sit 10th.
Toulouse, who finished third in the Top 14 last season, are currently lying second, two points behind Clermont.