Capt. Sir Thomas Moore received the honor during a ceremony at Windsor Castle that marked the first investiture the 94-year-old queen has taken part in since she began following strict stay-at-home orders in March during the pandemic.
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Measures were put in place to ensure that both the queen and Moore -- considered particularly vulnerable to the virus due to their ages -- were kept safe during the ceremony.
Moore met the queen outdoors in Windsor Castle’s Quadrangle, accompanied by his family for the special occasion.
Queen Elizabeth used the sword that belonged to her father, George VI, to tap Moore on his shoulders.
Moore tweeted his excitement Friday morning before the ceremony, writing, "Good Morning! Ready and raring to go for what is a very special day. Thank you for all the well wishes, as ever, overwhelmed by your support."
Moore gained international fame in April when he raised over $37 million for front-line National Health Service workers in the U.K.
Moore originally aimed to raise $1,000 for charity by walking laps in his garden while under lockdown in Buckinghamshire, England. He hoped to complete 100 laps before he turned 100 in late April.
Moore's online campaign exploded and by the time he reached his 100th birthday on April 30, the World War II veteran had raised tens of millions of dollars.
Moore also received a promotion from Queen Elizabeth to the rank of colonel and a special flyover to commemorate his achievements.
Friday marked a busy day for Queen Elizabeth, who attended the wedding of her granddaughter, Princess Beatrice, on the grounds of Windsor Castle before leading the investiture ceremony for Moore.
ABC News' Guy Davies and Julia MacFarlane contributed to this report.