John Lennon and Freddie Mercury's stamp collections are to be displayed at London's Stampex exhibition from September 14-17.
Both stars collected stamps in their childhoods, but gave up long before they hit the bigtime.
Lennon began collecting at the age of 10, after his cousin gave him his old stamp album.
He had a particular interest in issues from far flung places like New Zealand and America.
The album is well-known in both Beatles memorabilia and philatelic circles.
The Smithsonian's National Postal History Museum bought it for around $50,000 in a private sale in 2005.
Wilson Hume, the institution's late curator, told Smithsonian Magazine in 2005: "Typically, young boys aren't interested in rarity.
"They tend to concentrate on geography and colors.
"If they come back to collecting when they have more time and money, that's when collections become exceptional."
Mercury preferred stamps from his native Zanzibar alongside other British Empire issues.
His collection dates to between the age of nine and 12 and has been arranged with an eye for colour and pattern.
This year marks the 60th anniversary of Stampex - the biggest philatelic show in the UK.
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