The 100-year-old is being treated for pneumonia, his daughter Hannah said in a statement.
She said that Captain Sir Tom was already being treated for pneumonia when he tested positive for coronavirus.
After suffering breathing difficulties at home he was admitted to Bedford Hospital, she added.
In a statement posted on Captain Sir Tom Moore’s Twitter page, his daughter said: “I wanted to update everybody that today (Sunday 31 January) my father was admitted to hospital.
“Over the last few weeks he was being treated for pneumonia and last week tested positive for Covid-19.
“He was at home with us until today when he needed additional help with his breathing. He is being treated in a ward although he is not in ICU.
“The medical care he has received in the last few weeks has been remarkable and we know that the wonderful staff at Bedford Hospital will do all they can to make him comfortable and hopefully return home as soon as possible.
“We understand that everyone will be wishing him well. We are of course focussing on my father and will update you when we are able to.”
The message was signed off “Hannah x”.
( Captain Sir Tom was knighted by the Queen
/ AFP via Getty Images )Captain Sir Tom’s fundraising efforts raised more than £32 million for the NHS, walking 100 laps of his garden before his 100th birthday during the first national lockdown in April.
The veteran set out to raise £1,000 from his lockdown charity challenge but his efforts struck a chord with the nation, and praise and donations flooded in.
In acknowledgement of his efforts, he was knighted by the Queen during a unique open-air ceremony at Windsor Castle in summer 2020.
Public figures lined up to pay tribute to the centenarian.
Prime Minister Boris Johnson tweeted that Captain Sir Tom had “inspired the whole nation”.
“My thoughts are very much with @CaptainTomMoore and his family”, he wrote.
“You’ve inspired the whole nation, and I know we are all wishing you a full recovery.”
Michael Ball, who recorded a charity single with Captain Sir Tom that reached number one, tweeted: “Love and prayers for @captaintommoore and his lovely family as he battles this bastard of a virus. Stay strong Sir. We are all here for you.”