Team Sky's Mikel Landa is to switch to the rival Movistar team next season after signing a two-year contract.
The 27-year-old Spaniard, who missed out on a Tour de France podium by just one second last month, will race for the Spanish-based team in 2018 and 2019.
Landa played a crucial part in Chris Froome's Tour win, helping the Team Sky general in the crucial mountain stages and sacrificing his own hopes of a top-thee place in the general classification.
Movistar general manager Eusebio Unzue said: "It's great news for us. Being still a young rider and with everything that he has shown, he should be the rider who leads Spanish cycling for the next few years."
Landa, who recently won the Vuelta a Burgos and was a stage victor in this year's Giro d'Italia - where he also claimed the king of the mountains jersey - was a top three finisher in the 2015 Giro, taking two stage wins along the way.
The Spanish star, who has also won stages on the Vuelta a Espana, Giro del Trentino, Tour of the Basque Country and the Burgos, will challenge Nairo Quintana and Alejandro Valverde for No 1 billing at Movistar from next year.