Irish rider Nicolas Roche will join BMC Racing from Team Sky next season.
The 32-year-old helped Chris Froome win the 2015 Tour de France and claimed a stage victory at the 2015 Vuelta a Espana in a two-year stay with the British squad.
He will now become a domestique for BMC Racing team leaders Richie Porte and Tejay van Garderen, as well as pursuing his own goals at the 2017 Vuelta.
Roche said: "I'm super-excited because BMC Racing Team is a team that rides with a lot of the characteristics that I like.
"My main role will be to really support Richie Porte and Tejay van Garderen in their general classification ambitions, and hopefully I'll have a good go at the Vuelta a Espana."
Roche will officially move to BMC Racing on January 1, but the length of his contract has not been disclosed.
Meanwhile, Orica-BikeExchange have announced the signing of Roman Kreuziger on a two-year deal.
The 30-year-old Czech rider finished 10th at last month's Tour and looks set to become a domestique for Orica-BikeExchange team leaders Adam Yates, Esteban Chaves and Simon Yates in Grand Tours.
Kreuziger will officially move on January 1 from Tinkoff, who are folding at the end of the season.
Orica-BikeExchange sports director Matt White said: "Roman is a real game-changing signing for us. He is not only one of the classiest and strongest riders at WorldTour level, but he also brings a wealth of experience, having worked for the best GC [general classification] riders in the world.
"He will be one of the riders who can make the difference for our young riders at the Tour de France in the attempt to go for the podium."