A special postmark has been made to celebrate the upcoming 100th birthday of the Bedfordshire war veteran who has raised £29m for NHS charities.
Royal Mail will stamp all letters with the message from Monday ahead of Captain Tom Moore's big day on Thursday.
The postmark, which will be stamped on all post up until Friday, reads: "Happy 100th Birthday Captain Thomas Moore NHS fundraising hero 30th April 2020."
Captain Moore has become a national treasure after raising millions of pounds for NHS Charities Together by walking laps of his garden in Marston Moretaine near Bedford.
As of Monday morning, he'd raised more than £29m - a far cry from his initial target of £1,000.
"What Captain Thomas Moore has achieved is truly phenomenal, and this is reflected in the affection shown for him across the world," David Gold, director of public affairs and policy at Royal Mail, said.
"As Royal Mail works to keep the country connected during these challenging times, we are honoured to issue a special postmark in celebration of his 100th birthday."
Royal Mail said staff had already processed more than 100,000 birthday cards for Captain Moore, and a dedicated collection box has even been set up to deal with the deluge of good wishes.
"We continued to deliver the many tens of thousands of birthday cards from well-wishers across the UK and abroad as people look to show their gratitude for all he has achieved on a more personal level.
"We would like to extend our own best wishes and congratulations to him from everyone at Royal Mail."
Prime Minister Boris Johnson paid tribute to Captain Moore on Monday morning, and urged the country to show the same "spirit and optimism."
"If we, as a country, can show the same spirit, optimism and energy shown by Captain Tom Moore, who turns 100 this week, then I have absolutely no doubt we will beat it," he said.
"Together, we will come through this all the faster and the United Kingdom will emerge stronger than ever before."