From 21 August a sheet of eight stamps will be available showing the proud parents and bearing the motif: "Announcing the birth of HRH Prince George Alexander Louis."
A special gold foil postmark with the words: "It's a boy" will be added to the tribute.
Peter Jennings, a fellow of the Royal Philatelic Society, said: "The stamps of King George V and King George VI are extremely popular with stamp collectors. They are collected and treasured.
"Now is a great opportunity to start a collection of the stamps of the baby boy destined to be the future King George VII."
The royal couple previously appeared on stamps ahead of their wedding when portraits taken by Mario Testino, Princess Diana's favourite photographer were used.
William has also been awarded this honour on two other occasions:to mark the Queen Mother's 100th birthday on August 4, 2000, and three years later to mark his 21st birthday.