Conchita Wurst, the bearded Austrian drag queen who became a gay rights icon after winning the Eurovision Song Contest in 2014, said in an Instagram post late on Sunday that she is HIV-positive.

"I have been HIV-positive for many years," the 29-year-old pop singer, whose real name is Tom Neuwirth, told her nearly 300,000 followers, adding that she had been forced into revealing her status by a former partner.

"This is actually irrelevant to the public, but an ex-boyfriend is threatening to go public with this private information, and I will not give anyone the right to frighten me or affect my life," Wurst said.

The singer, whose distinctive look combines long dark hair, painted nails and groomed black beard, shot to fame after winning the long-running music contest with power ballad "Rise Like a Phoenix".

She was later invited to perform at the United Nations and hailed by U.N. Secretary-General Ban Ki-moon for fighting discrimination.

Wurst said her treatment for HIV, which is spread when infected fluid enters the bloodstream, was going well.

"Since I received the diagnosis, I have been in medical treatment, and for many years without interruption I have been below the detection limit, which means I am unable to transmit the virus," Wurst said on Instagram.

More than 70 million people globally have been infected with the HIV virus and 35 million have died since the HIV/AIDS epidemic in the 1980s, according to the World Health Organisation.