John Surtees - the only man to win grand prix world championships on two and four wheels - has died at the age of 83.
The Englishman won four 500cc motorcycling titles from 1956 to 1960, before switching to cars and topping the Formula One drivers' standings for Ferrari in 1964.
Surtees' death was confirmed via a statement from the Henry Surtees Foundation - a charity established in memory of his son, who died aged 18 after being hit by a wheel during a Formula Two race at Brands Hatch in 2009.
"It is with great sadness that we announce the death of our husband and father, John Surtees CBE," read the statement from his family.
"John, 83, was admitted to St George's Hospital, London in February with an existing respiratory condition and after a short period in intensive care he passed away peacefully this afternoon [Friday]. His wife, Jane and daughters, Leonora and Edwina were by his side.
"John was a loving husband, father, brother and friend. He was also one of the true greats of motorsport and continued to work tirelessly up until recently with The Henry Surtees Foundation and Buckmore Park Kart Circuit.
"We deeply mourn the loss of such an incredible, kind and loving man as well as celebrate his amazing life. He has set a very real example of someone who kept pushing himself at his peak and one who continued fighting until the very end."
John Surtees, Motorsport legend and 1964 World Champion with Ferrari, passed away. Our thoughts are with his family pic.twitter.com/dVzAHSGo2A-- Scuderia Ferrari (@ScuderiaFerrari) March 10, 2017
Surtees was awarded an MBE in 1959 before picking up an OBE in 2008 and a CBE as part of the 2016 New Year honours, and was also inducted to the International Motorsports Hall of Fame in 1996.
We are so sad to hear of the passing of John Surtees. He was such a gentleman and a true legend. Our thoughts are with his family & friends. pic.twitter.com/XKRXtEq7Fe-- WILLIAMS RACING (@WilliamsRacing) March 10, 2017
Damon Hill, whose father Graham finished second to Surtees in 1964, was among the first to pay tribute, tweeting: "Such a lovely man. We have lost a true great motorsport legend. RIP John."
Such a lovely man. We have lost a true great motorsport legend. RIP John. #JohnSurtees-- Damon Hill (@HillF1) March 10, 2017