Italian cyclist Michele Scarponi has been killed after being hit by a minibus while out riding in Filottrano, Italy.
The 37-year-old left home early on Saturday morning for a training ride during which he was involved in a head-on collision with a minibus at a crossroads.
He had just returned from finishing fourth in the Tour of the Alps in Trento on Friday after winning the opening stages of the race.
His team, Astana, announced his death on Saturday morning, saying it was a "tragedy too big to be written", changing their Twitter banner to a photo of the cyclist and writing "Ciao Michele".
A helicopter took him to a hospital in Ancona, but local media reported that the athlete died on impact.
In a statement the team said: "We left a great champion and a special guy, always smiling in every situation, he was a real milestone and a landmark for everyone in the Astana Pro Team."
After returning home from Trento with his masseur, the father-of-two had spent Friday evening at home with his family.
During the evening he had posted a photo wearing the leader jersey he had won in his last race, with his twin sons riding on his back.
A professional cyclist since 2002, Scarponi was awarded 2011 Giro d'Italia victory when Alberto Contador was stripped of the title for doping. He was slated to lead Astana at the 2017 Giro.
British road cyclist Mark Cavendish wrote in tribute on Twitter: "Absolutely devastating to see the tragic news about @MicheleScarponi. One of the nicest guys you could ever meet. RIP my friend."
Belgian rider Gianni Meersman wrote "RIP @MicheleScarponi one of the funniest riders" alongside a picture of the rider with a blue and yellow parrot on his shoulder.
Scarponi leaves behind his wife Anna and four-year-old twin sons James and Thomas.