In the eloquent letter, published on his website, Stephen describes the regular persecution that gay people in Russia suffer, including 'corrective' raping of lesbians and gay men and gay men and women beaten to death by neo-Nazi thugs.
The 2014 Winter Olympics are planned to take place in Russian city Sochi.
The letter comes in the wake of a new bill signed into law in June by Russian President Vladimir Putin, banning the “propaganda of nontraditional sexual relations.” Public displays of affection, events promoting gay rights like pride rallies, being gay or being suspected gay could land citizens or tourists in jail.
Stephen writes: 'The Summer Olympics of 2012 were one of the most glorious moments of my life and the life of my country. For there to be a Russian Winter Olympics would stain the movement forever and wipe away any of that glory'
He also draw parallels between the Olympics of 1936, which took place in Nazi Germany, and those set to take place in Russia. He writes 'consider the stain on the Five Rings that occurred when the 1936 Berlin Olympics proceeded under the exultant aegis of a tyrant who had passed into law an act which singled out for special persecution a minority whose only crime was the accident of their birth.
In his case he banned Jews from academic tenure or public office, he made sure that the police turned a blind eye to any beatings, thefts or humiliations afflicted on them, he burned and banned books written by them.'
He continues 'Putin is eerily repeating this insane crime, only this time against LGBT Russians. Beatings, murders and humiliations are ignored by the police. Any defence or sane discussion of homosexuality is against the law'
'I am gay. I am a Jew. My mother lost over a dozen of her family to Hitler’s anti-Semitism. Every time in Russia (and it is constantly) a gay teenager is forced into suicide, a lesbian “correctively” raped, gay men and women beaten to death by neo-Nazi thugs while the Russian police stand idly by, the world is diminished and I for one, weep anew at seeing history repeat itself.'
The letter goes on to outline the powers the Olympic committee have to act against discrimination and, directly to David Cameron, writes 'In the end I believe you know when a thing is wrong or right. Please act on that instinct now.'
Signing off 'Yours in desperate hope for humanity, Stephen Fry'
Read the full letter here
Sign the petition to support to eliminate anti-gay laws in Russia here