The new stamps which were unveiled Tuesday, feature both informal and formal photographs of the couple.
Two pictures of the couple taken by fashion and celebrity photographer Mario Testino will be printed on stamps, which can be ordered beginning April 7.
The Royal Mail said the collectibles have been approved by William and will be released on April 21, the birthday of Queen Elizabeth II.
William has been featured on stamps twice before - to mark the Queen Mother's 100th birthday on August 4, 2000, and three years later to mark his 21st birthday.
Transport for London also announced Tuesday that it will feature the couple on special commemorative transit cards.
The Associated Press contributed to this report.