Formula One world champion Lewis Hamilton says he lost 4kg (8.8lb) after contracting coronavirus.
He posted pictures of himself at the gym on Instagram, hours after being named 2020 BBC Sports Personality of the Year on Sunday.
“I’ve lost 6kg over the past two months – four of which when I got Covid,” said the 35-year-old.
“I’ve lost so much muscle. I’m starting from a low point in strength now, not fun but I’m determined to get my strength back and to be 100% again.
“No pain, no gain.”
Hamilton had a memorable 2020 on the track, equalling Michael Schumacher’s record of seven world titles with his fourth consecutive championship.
He also surpassed Schumacher’s total of 91 grand prix wins.
His deal with Mercedes runs out at the end of 2020 and talks are at an early stage over a renewal.
Last week, team boss Toto Wolff said there was no rush to finalise a new contract and it could wait until well into the new year.