Benedict Cumberbatch and Stephen Fry are among signatories of an open letter asking the British government to pardon 49-thousand men who were prosecuted for being gay.
Members of World War Two codebreaker Alan Turing's family have also signed.
Cumberbatch plays Turing in The Imitation Game, he was convicted of gross indecency in 1952 and killed himself in 1954. He was pardoned in 2013.
The signatories have asked the Duke and Duchess of Cambridge to help with their campaign.