Colombian Nairo Quintana, who won stage 18 of the Tour de France on Thursday, will ride for French team Arkea-Samsic next year, his father said.
The 29-year-old two-time Grand Tour winner - the most decorated cyclist in Colombia's history - has spent the last seven years with Spaniards Movistar.
"Nairo is changing teams, he's going to Arkea," Luis Quintana told Bogota's Blu Radio.
"I'm telling you, Colombians, that Nairo will probably do very well."
Quintana exploded onto the European scene in 2012, his first season with Movistar, winning two stage races in the Vuelta a Murcia and Route du Sud, as well as claiming a stage victory at the prestigious Criterium du Dauphine.
The next year he shocked his experienced Spanish team-mate Alejandro Valverde, the current world champion, by out-performing him in riding to second place at the Tour de France behind Briton Chris Froome, now a four-time winner.
Success kept coming for Quintana as he won the 2014 Giro d'Italia, came second in the Tour the next year and then won the Vuelta a Espana in 2016.
He also won important stage races such as Tirreno-Adriatico and the Tour of Romandie.
But since finishing second in the 2017 Giro, his results have been a disappointment.
He could finish only 12th at the Tour that year and 10th 12 months later, while he was outside the top 10 in the current race until his victory in the Alps propelled him up to seventh.
Until then he'd been lagging behind two team-mates in 39-year-old Valverde and Spaniard Mikel Landa, even claiming on Wednesday that he was now working for the latter.
Landa was seventh in the standings until Quintana's victory, leaving the Colombian now a minute ahead of his team-mate with two Alpine stages to come before Sunday's procession into Paris.
Arkea haven't commented on the move but Movistar team manager Eusebio Unzue suggested on Monday that Quintana was on his way out.
"Nairo has given us so many glorious days and I don't rule out that he will have some more, but it's been a couple of years now that he's not been at the great level we saw before," Unzue told Spain's Cadena Ser.
Quintana rolled back the years on Thursday, though, getting clear in a breakaway and then attacking on the final climb up the imposing Galibier mountain to claim his third stage victory at the Tour following one each in 2013 and last year.
He's now less than four minutes behind overall leader Julian Alaphilippe, from France, a minute ahead of Landa and two clear of Valverde.