First-class stamps depicting 10 of the sports which will be included in the London 2012 Olympic and Paralympic Games have been unveiled.
Artists have designed images of events including athletics, canoeing, diving and the Paralympic sport of boccia.
The stamps will go on sale in October, and two more sets showing another 20 sports will be launched in later years.
The Royal Mail said the aim was "to highlight both the sporting and cultural legacy" of the Games.
Previously, limited edition stamps were created to mark London's winning of the Games and the handover of the Olympic flag from China to the UK.
'Festival of sport'
The latest collection features images of three Paralympic sports - dressage, archery and the less well-known event of boccia.
The latter sees competitors trying to land coloured leather balls as close as possible to a white "jack" ball.
There are also seven stamps featuring the Olympic disciplines of canoe slalom, track athletics, diving, judo, badminton, weightlifting and basketball.
London 2012 chairman Lord Coe said: "It is a huge honour to have stamps created in celebration of the Games and we look forward to working with Royal Mail over the next three years.
"These stamps will be a wonderful way to celebrate the London 2012 Games and mean that the whole country can get involved in this fantastic festival of sport between now and 2012."
The collection goes on sale on 22 October, followed by later sets showing other sports in 2010 and 2012.
Julietta Edgar, the Royal Mail's head of special stamps, said: "Royal Mail has always been there to celebrate and commemorate significant moments in our history and the London 2012 Olympic Games is one of the greatest events on the planet.
"We hope these stamps play their part in the countdown to the Games, but also to highlight both the sporting and cultural legacy of this wonderful event."