Seven-time Formula 1 world champion Lewis Hamilton has revealed he lost 4 kilograms in weight while suffering from COVID-19 during a 10-day period last month.

The 35-year-old Briton missed the penultimate race in Bahrain after contracting coronavirus but recovered in time to contest the season-ending Abu Dhabi Grand Prix.

In his latest post on Instagram, Hamilton admitted he was “starting from a low point in strength” as he begins training for 2021 having shed a total of 6kg over the past two months.

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“I’ve lost 6kg over the past two months, 4 of which I lost when I got COVID,” Hamilton wrote. “I’ve lost so much muscle.

“Starting from a low point in strength now, not fun but I’m determined to get my strength back and to be 100% again.”

Hamilton has kept his battle with coronavirus relatively private, refusing to go into details about his experience when asked in Abu Dhabi, though he did stress he was “not 100%” fit, while Mercedes F1 boss Toto Wolff indicated at the previous race in Bahrain that Hamilton was “not great”.

After the season-ending race, Hamilton said he was “happy to be alive” after he rounded out a historic year by finishing in third place on the podium despite feeling “destroyed”.

"Covid is no joke, I never thought it was,” he added. “I knew at some stage if I got it it would be tough because there are people out there losing their lives.

“So I knew it was serious. I always find it very strange to see world leaders laughing it off like it is nothing.

"To be able to come back here this weekend, I knew I wouldn't physically be where I have been the rest of the season but I made it. Where there is a will, there is a way.”

Hamilton concluded a mightily successful year by winning BBC Sports Personality of the Year for the second time.