Colourful American pop star Lady Gaga has been declared an honorary citizen of Sydney for her \"unwavering support\" of gay rights as she delighted fans with surprise shows at two city nightspots. The cryptic pop diva was given the honour during a low-key tour of Sydney, which will feature just one invite-only concert at the city\'s Town Hall for 1,000 people, as a token of gratitude for her gay rights work. \"Lady Gaga has been a powerful force for the gay and lesbian community in Sydney, and we have a rare honour for people whose achievements embrace the ideals and spirit of our city -- the title of \'Honorary citizen of Sydney\',\" said Lord Mayor Clover Moore on Tuesday. \"I am extending that honour to Lady Gaga.\" Moore said the award paid tribute to the artist\'s use of her \"star power to focus the world\'s attention on the prejudice still directed at gay men and women.\" Despite being among the world\'s gay and lesbian capitals annually hosting the renowned Mardi Gras gay pride march Moore said Sydney\'s same-sex couples were still denied the right to marry under national law. \"The law needs to change. Every Australian who wants to make a life commitment to the person they love should be able to do so. And have that commitment equally recognised and supported by the law,\" she said. Born Stefani Germanotta, Lady Gaga used an interview on prime time television Monday night to call for Australian Prime Minister Julia Gillard to legalise same-sex marriage. \"I am so against the way certain laws and restrictions send messages that one person is better than another,\" she told the Nine Network. \"I urge all of you to mobilise your voices so the prime minister can hear you scream that you want to be equal.\" The prime minister was quick to pour cold water on Lady Gaga\'s calls. \"For me I think marriage and the Marriage Act has had a particular status in our society and it should keep that status,\" said Gillard. Ranked this year\'s most powerful celebrity by Forbes magazine, Lady Gaga, 25, spoke out last year against the now repealed US policy which forced gay servicemen and women to keep their sexuality secret or face dismissal. Hundreds of fans queued for hours at Sydney nightspots, Arq and Nevermind, Monday night after the singer let slip on Twitter that she would be making a guest appearance. \"Thinking of going out in Sydney Tonight. How I wish we had a show. NEVERMIND, don’t listen to me. Maybe I’ll just go for a walk in the pARQ,\" she wrote.