Stephen Fry said he believes the Winter Olympics in Sochi will not be moved or boycotted after David Cameron said he did not support a boycott.
"My feeling now is that it isn't going to change," Fry told BBC News.
The broadcaster said his call to move the Games to another country was "probably not realistic in terms of being likely".
He added: "But it's realistic to call for it, and if it makes anybody look online and see how gays are being treated in Russia - it's horrifying and it's getting worse."
Stephen Fry said the Prime Minister "may be right" after he ruled out boycotting the 2014 Winter Olympics in Russia, but asked, "Is there nothing we can do?"
After David Cameron said it was "better to challenge prejudice as we attend" the event in Sochi, Fry wrote on Twitter:
.@david_cameron PM, you may be right. Would that have been true in 1936? But is there nothing we can DO? Putin grow and grows in confidence
Lots of people popping down to Whitehall to make their feelings known. What to wear, what to wear?
David Cameron said he believes it would be "better to challenge prejudice as we attend, rather than boycotting the Winter Olympics" in Russia.
In response to a letter Stephen Fry wrote urging him to back the boycott, the Prime Minister wrote on Twitter:
1/2 Thank you for your note @stephenfry. I share your deep concern about the abuse of gay people in Russia...
New laws in Russia banning the promotion of "non-traditional relationships" have raised questions about the country's suitability to host the 2014 Winter Olympics.
Pink News publisher Benjamin Cohen explains what the laws could mean in practice, and why the International Olympic Committee may be prompted to look again at its choice of host city.
The president of the International Olympic Committee has said he is waiting for clarification from the Russian government on the anti-gay law that is overshadowing preparations for the Winter Games in Sochi.
"We are waiting for the clarifications before having the final judgement," Jacques Rogge told reporters.
"The Olympic charter is clear," Rogge said. "A sport is a human right and it should be available to all, regardless of race, sex or sexual orientation."
A spokesman for the British Olympic Association has said his organisation believes a boycott of the Winter Olympics in Sochi would serve only to "penalise athletes".
Darryl Seibel told ITV News that Olympic bosses are monitoring the situation in Russia closely and that the safety of athletes is a top priority.
A petition calling on the International Olympic Committee (IOC) to relocate the 2014 Winter Games away from Russia has garnered almost 130,000 signatures.
Petitioners want the Games to be taken away from Sochi because of laws in Russia which they say discriminate against LGBT people. They suggest relocating to Vancouver in Canada, which hosted the Games in 2010.
A Government spokeswoman said:
We remain greatly concerned about the growing restrictions on LGBT freedoms in Russia and have repeatedly raised our concerns, including at the 2013 UK-Russia Human Rights dialogue in May.
The Prime Minister outlined our concerns with President Putin during a meeting in Downing Street in June ahead of the G8 Summit.
We are working closely with the IOC and the BOA to ensure that the Games take place in the spirit of the Olympic Charter and are free from discrimination.
Stephen Fry has urged the Prime Minister to support a campaign to strip Russia of the 2014 Winter Olympics amid concerns about anti-gay laws passed in the country.
In an open letter on his website, the broadcaster said President Vladimir Putin "is making scapegoats of gay people" and "cannot be seen to have the approval of the civilised world."
Politicians in Russia's lower house of parliament, the Duma, have passed a law imposing heavy fines for providing information about homosexuality to people under 18.
Last month the IOC said it had "received assurances from the highest level of government in Russia that the legislation will not affect those attending or taking part in the Games."
Stephen Fry has thanked the Queen for giving royal assent to the Bill that passes same-sex marriage into law: