Hitzlsperger's announcement, in German magazine Die Zeit, makes him the first Germany international to reveal that he is gay.

Russia, which will stage the Winter Olympics in Sochi next month, has come under international pressure after President Vladimir Putin in June approved a law that bans the promotion of homosexuality to minors.

Calling for further pressure, Hitzlsperger told British newspaper The Guardian, in an interview published late on Wednesday: "It's important to face up to nations that discriminate against minorities, sexual or otherwise.

"I'm fine with the fact that my story will be mentioned in relation to the Games, because the situation in Russia is something that needs to be talked about.

"I'm curious to see what will happen. I'm sure that some athletes will make a stand."

Figures from sport and politics across Europe voiced their support for Hitzlsperger, but his announcement fell on a day when Paris Saint-Germain's Brazilian defender Alex created a row about homophobia.

Speaking in a documentary about religion due to be broadcast on French pay TV company Canal+, the born-again Christian said: "God created Adam and Eve, not Adam and Yves."

Reacting to Alex's comments, Hitzlsperger said: "You'll always have those guys, but it's sad that they don't think a little deeper about what they're saying. I feel sorry for them, really."

In an interview to be published in Thursday's edition of Die Zeit, Hitzlsperger, 31, revealed: "I am declaring my homosexuality because I want the question of homosexuality in the world of professional sport to be out in the open."

But he admitted that reaching the decision to come out had been "a long and difficult process".

Hitzlsperger, capped 52 times by Germany between 2004 and 2010, added: "It is only in recent years I have come to realise I preferred living with a man."

The midfielder, who hung up his boots at the end of last season, plied his trade in Germany, England and Italy with Aston Villa, Everton, Wolfsburg and Lazio, among others, before retiring last year.

Hitzlsperger said he had decided to come out because now was "a good time" for him and because he wanted to promote the discussion of homosexuality in professional sport.

"I've never been ashamed of the way I am," he added, although he conceded that "in England, Germany or Italy, homosexuality is not taken seriously as an issue, at least not in the dressing room".

Olympic diver Greg Louganis, NBA basketball player John Amaechi and tennis great Martina Navratilova are among the leading sports stars to have previously come out, but openly gay footballers are a rarity.

Former United States international Robbie Rogers revealed he was gay in February last year and subsequently came out of early retirement to join the Los Angeles Galaxy.

Justin Fashanu, the former Norwich City and Nottingham Forest striker, became the first openly gay player in the English top flight, but he committed suicide eight years after coming out.

Amaechi tweeted on Wednesday: "Congratulations to Thomas Hitzelsperger (sic) -- welcome to the club!"

Hitzlsperger's former Germany colleague Lukas Podolski reacted to the news on Twitter by saying: "Brave and right decision. Respect, Thomas Hitzlsperger. His outing is a important sign of our time."

Hitzlsperger's former club Villa tweeted: "Everyone who knows Thomas from his time here at Villa has great respect for him, not only as the fine player he was but also as a man."

British Prime Minister David Cameron, a Villa supporter, also expressed his admiration for the player.

"As an #AVFC fan, I've always admired what Thomas Hitzlsperger did on the pitch -- but I admire him even more today. A brave & important move," he wrote on Twitter.

Outspoken Queens Park Rangers midfielder Joey Barton also took to Twitter to add his comments.

Praising Hitzlsperger's "courage", Barton also criticised Alex's comments, writing: "To be religious extremist, you must first be extremely dumb in my opinion. Alex from PSG simply confirms my theory with his comments today."

Meanwhile, Italy's Gay Center gave its backing to Hitzlsperger.

"Are there gay footballers in Italy? We believe so. They should do the same as Hitzlsperger and come out publicly," said a statement by the organisation.

"Top athletes coming out would relay a positive message, especially to young people, and help to combat homophobia."