From Monday to 1 May all letters will be stamped with the postmark to celebrate the birthday of the war veteran who raised more than £28m for the NHS by walking laps of his garden.
The Royal Mail postmark reads: “Happy 100th Birthday Captain Thomas Moore NHS fundraising hero 30th April 2020.”
His original target of £1,000 was broken in around 24 hours and he extended his challenge to 200 laps after he completed the first 100 two weeks ahead of schedule.
The postal recognition comes after Royal Mail had to adapt its sorting machines in the South Midlands Mail Centre to re-route all post to Captain Tom into a dedicated collection box.
He added: We would like to extend our own best wishes and congratulations to him from everyone at Royal Mail.”
Capt Moore, of Bedfordshire, was awarded the Pride of Britain Award for his fundraising efforts.
Earlier this week he became the oldest person to score a UK number one single for his rendition of “You’ll Never Walk Alone” with Michael Ball and The NHS Voices of Care Choir.
Speaking on Monday morning after returning to work, Prime Minister Boris Johnson referred to Capt Moore's spirit, and wished him a happy birthday.
"And so I say to you finally if you can keep going in the way that you have kept going so far if you can help protect our NHS to save lives, and if we as a country can show the same spirit of optimism and energy shown by Captain Tom Moore, who turns 100 this week, if we can show the same spirit of unity and determination as we have all shown in the past six weeks then I have absolutely no doubt that we will beat it together, we will come through this all the faster, and the United Kingdom will emerge stronger than ever before."
Additional reporting by PA