Sir Elton says he is currently arranging to meet Vladimir Putin to discuss gay rights.
The pop singer has said he wants to talk to the president about his “ridiculous” attitude to the issue – but previously fell victim to prank callers pretending to be the Russian leader.
Speaking to BBC Radio 4, Elton said he had since received a genuine call from the president.
“He was very affable, he was very apologetic, he was very sincere.
“As soon as I can get a date in my diary that coincides with him, then I will be going… to Moscow and I will meet him,” he told the Today programme.
Earlier this week, Northern Ireland’s Assembly narrowly voted in favour of same-sex marriage for the first time – but the largest party in the devolved parliament, the Democratic Unionists, vetoed any change in the law, on the basis that only four unionists had backed the proposal.
“The politicians need to get their act together and enter the 21st Century,” declared Elton, adding he was “sure” that a same-sex marriage law would “sail in” if the public were allowed to vote.
A survey by the BBC and Irish broadcaster RTÉ published yesterday suggested that almost two-thirds of people in Northern Ireland would feel comfortable if a family member had a same-sex marriage.
Elton rejected suggestions he would avoid playing concerts in Northern Ireland as a result.
“I’m not a politician,” he said, “but I will speak out for rights when I can, and especially LGBT rights as I’m an elderly gay citizen.”
The philanthropist has also teamed up with the US government to donate $10m (£6,5m) to organisations in sub-Saharan Africa who work with lesbian, bisexual, gay and transgender people suffering from Aids or HIV. He says the stigmatisation they suffer “allows AIDS to spread”.
“I think it’s going to make an awful lot of difference because we can get medicine to people who are being ostracised,” he said.
But Elton believes he’ll have to “tread carefully” around politicians and religious leaders in the continent, many of whom insist that homosexuality is an aberration.
“It’s not going to be easy. But it’s getting the medicine to the people who need it on a daily basis so the HIV and AIDS epidemic doesn’t spread any further.
“It is spreading because people are afraid for their lives, they’re afraid to get tested, they’re afraid to say they’re gay. Unless we nip this in the bud now, it’s going to cause awful havoc.”
Also during the interview, Elton mentioned Pope Francis. He considers him to be an “ally” against conservative bishops in Africa in his views on same-sex relationships.
“My sly bet is yes he is. He’s just had the synod in Rome and I think he’s fighting an uphill battle against the African cardinals and bishops.”
Elton said his message to the Pope was: “Keep going, keep pushing it. Change is very hard, especially in the Catholic Church, you don’t get things done immediately, you’re not going to persuade people, just keep going and keep going and eventually the wall will fall. I think he’s on our side.”
The vocalist, who is in a same-sex marriage, added: “I would love to meet him. I’m not a Catholic but from the first day he was elected he tried to bring a new message and change the Church and bring it into the 21st century. To be a inclusive Church. He has brought hope and change.”