Captain Sir Tom Moore has been admitted to hospital with coronavirus, his daughter has said.
The 100-year-old, who raised almost £33m for the NHS, was taken to Bedford Hospital after requiring help with his breathing, Hannah Ingram-Moore said on Twitter.
She said he had been treated for pneumonia over the past few weeks and last week tested positive for COVID-19. Mrs Ingram-Moore said her father was not in intensive care.
A spokeswoman for the family said Capt Sir Tom had not yet received the COVID-19 vaccine due to the medication he was on for pneumonia.
Prime Minister Boris Johnson tweeted: “You’ve inspired the whole nation, and I know we are all wishing you a full recovery.”
The Army veteran won the nation’s hearts by walking 100 laps of his garden in Marston Moretaine, Bedfordshire, before his 100th birthday during the first national lockdown.
He was knighted by the Queen in July.
(With input from agencies)