LONDON (AP) — Capt. Tom Moore, the World War II veteran who walked into the hearts of a nation in lockdown as he shuffled up and down his garden to raise money for health care workers, has died after testing positive for COVID-19. He was 100.

His family announced his death on Twitter, posting a picture of him behind his walker in a happy moment, ready for an adventure.

“The last year of our father’s life was nothing short of remarkable. He was rejuvenated and experienced things he’d only ever dreamed of,’’ the family’s statement said. “Whilst he’d been in so many hearts for just a short time, he was an incredible father and grandfather, and he will stay alive in our hearts forever.’’

Captain Tom, as he became known in newspaper headlines and TV interviews, set out to raise 1,000 pounds for Britain’s National Health Service by walking 100 laps of his backyard. But his quest went viral and caught the imagination of millions stuck at home during the first wave of the pandemic. Donations poured in from across Britain and as far away as the United States and Japan, raising some 33 million pounds ($40 million).

For three weeks in April, fans were greeted with daily videos of Captain Tom, stooped with age, doggedly pushing his walker in the garden. But it was his sunny attitude during a dark moment that inspired people to look beyond illness and loss.

“Please always remember, tomorrow will be a good day,” Moore said in an interview during his walk, uttering the words that became his trademark.

When Captain Tom finished his 100th lap on April 16, a military honor guard lined the path. The celebration continued on his birthday a few days later, when two World War II-era fighter planes flew overhead in tribute. Moore, a plaid blanket over his shoulders, pumped a fist as they roared past.

In July, he was knighted by Queen Elizabeth II in a socially distanced ceremony at Windsor Castle, west of London. The 94-year-old monarch used an impossibly long sword to confer the honor as Moore, wearing his wartime medals on his chest, leaned on his walker, beamed and became Sir Tom.

“I have been overwhelmed by the many honors I have received over the past weeks, but there is simply nothing that can compare to this,″ he tweeted after the ceremony. “I am overwhelmed with pride and joy.”

Queen Elizabeth II plans a private message of condolence to the family, Buckingham Palace said.

“Her Majesty very much enjoyed meeting Capt. Sir Tom and his family at Windsor last year,” the palace said in a statement. “Her thoughts, and those of the Royal Family, are with them, recognizing the inspiration he provided for the whole nation and others across the world.”

Flags were lowered at Prime Minister Boris Johnson’s Downing Street office. The British leader described Moore as a “hero in the truest sense of the word.”

Born in Keighley, West Yorkshire, on April 30, 1920, Moore completed an apprenticeship in civil engineering before being drafted into the army during the early months of World War II. After being selected for officer training, he rose to the rank of captain while serving in India, Burma and Sumatra.

After leaving the army in 1946, Moore went to work for the family construction firm. After that failed, he became a salesman and later a manager for building materials companies. When the concrete company he was working for was threatened with closure, Moore rounded up a group of investors and bought it, preserving 60 jobs.

Along the way, he divorced his first wife and fell in love with his employer’s office manager, Pamela. The couple married, had two daughters and eventually retired to Spain, but returned to England after Pamela Moore became ill.

After his wife died in 2006, Moore moved to the village of Marston Moretaine in Bedfordshire to live with his younger daughter, Hannah, and her family.

The former motorcycle racer slowed down at age 98 after he fell and broke his hip in 2018. A walker replaced his Skoda Yeti, but he kept moving.

During a backyard barbecue in early April of last year, Moore’s family challenged him to walk the entire length of the 82-foot driveway. After he made it to the end, his son-in-law encouraged him to keep going, offering to pay 1 pound for every lap and suggesting a goal of 100 laps by Moore’s 100th birthday.

FILE – In this Aug. 3, 2020 file photo, Captain Sir Tom Moore walks down a guard of honour during a visit to the Army Foundation College in Harrogate, England, as part of his new role as Honorary Colonel of the Northern military training establishment. Tom Moore, the 100-year-old World War II veteran who captivated the British public in the early days of the coronavirus pandemic with his fundraising efforts, has died, Tuesday Feb. 2, 2021. (Danny Lawson/PA via AP, File)

Danny Lawson