Michael Douglas and Matt Damon have become the latest celebrities to back a campaign to have historic gay sex offences expunged.

The campaign, which is backed by Stephen Fry and Benedict Cumberbatch, estimates that at least 49,000 men were convicted under gross indecency laws.

An open letter signed by Fry and Cumberbatch, last week asked the Duke and Duchess of Cambridge to join the campaign, but they declined.

Douglas and Damon starred as Liberace and his lover Scott Thorson in the film about his life ‘Behind the Candelabra’.

Other backers include Jessica Alba, Ryan Reynolds, Channing Tatum and Bryan Cranston, Keira Knightley, director Sam Taylor-Johnson, actor Matthew Goode, and moviemaker Lee Daniels.

An apology for Alan Turing was issued by then Prime Minister Gordon Brown in 2009, and the Queen in 2013 granted a posthumous pardon under the Royal Prerogative of Mercy.

Campaigners argue that all men who were convicted should be granted a pardon.

Those convicted under such laws are able to have their criminal records wiped out, but have to apply in order to be able to do so.