Nicolas Portal, the sports director of British cycling outfit Team Ineos, died suddenly at his home in Andorra aged 40, his team said on Tuesday.
A hugely popular figure on the cycling circuit, affable Frenchman Portal took part in the Tour de France six times as a rider and retired in 2010 after diagnosis of an irregular heartbeat.
After becoming Team Sky's sports director in 2013 he helped guide Chris Froome to his first Tour win, and was still in the job with Ineos at the time of his death.
"It is with the greatest sadness that we announce the passing of our much loved team-mate, colleague and friend Nico Portal who died suddenly this afternoon at his home in Andorra," an Ineos statement said on Tuesday.
"We are all overcome with grief at this terrible news and would ask everyone to respect the family's privacy at this difficult time.
"RIP Nico - your spirit will always be with us on the road and you will forever be in our hearts."
Four-time Tour winner Froome remembered Portal's kindness in condolences to his family.
"My thoughts are with Nico's wife and children tonight. He was the kindest, happiest guy I knew and always lived life to the fullest," Froome wrote on Twitter.
Portal started out with four years at French outfit AG2R and spent another three years with the Caisse d'Epargne outfit, which is now the top Spanish team Movistar.
He finally raced with Sky, who kept him on after his forced retirement.
He was part of the Sky setup which took Bradley Wiggins to Tour de France victory in 2012 and had a growing influence as Chris Froome (2013 and 2015-2017) and Geraint Thomas (2018) won the biggest prize in cycling before Egan Bernal took the honours for Team Ineos - previously Team Sky - last year.
Bernal remembered Portal as a cool-headed, inspirational leader who was always ready with a smile.
"From the beginning he was always there in all my important moments in this sport," said the 23-year-old reigning Tour champion.
Completely fluent in English, Spanish and French, Portal was not only a great communicator but a popular man with cyclists, fans and media.
Up-and-coming Ineos star Tao Geoghegan Hart called him an inspiration on a social media post.
"I have never met someone Nico didn't have time for. I never met someone who didn't think the world of Nico. He was a true inspiration," he wrote
"His energy, his humility & his passion for life shone so brightly. Nico Portal, it was an honour to work with you. We will all miss you immensely."
Ineos' key rival on the cycling scene, Dutch outfit Team Jumbo Visma, also sent condolences.
"What sad and terrible news! Our sincere condolences to family & team," they said in a Twitter message.