Appearing on the Ten Network's news and chat show The Project in support of the push to legalise gay marriage, Szubanski was introduced to rousing applause from the studio audience and almost broke down when talking about the pressures she had felt speaking openly could place on her career.

"I absolutely identify as gay and for a very long time have," Szubanski said.

However, she also offered a slightly more complex take on her sexuality. "I am absolutely not straight," she said. "I wouldn't define myself as bisexual either. I would say I am gay-gay-gay-gay-gay-gay-a little bit not gay-gay-gay-gay. Unfortunately there's not actually a word to describe me so I have to express myself through the medium of the dance."

The 50-year-old comic actor said her family, friends and colleagues had known of her sexuality for years, but coming out publicly was not something she chose to do lightly.

"There's a difference between living your life openly and living your life absolutely publicly, and that thing of 20 million people knowing your business is stressful," she said.

The woman who famously signed on as an ambassador for weight-loss brand Jenny Craig in 2008 admitted she had been so stressed on Monday, when news of her impending announcement broke, that "I demolished a whole packet of Tim Tams".

Szubanski said she chose to come out on Valentine's Day because "we live in a democracy and one in 10 people, which is the number of gay people, are not represented equally".

Saying she would understand if people wondered why she hadn't done it sooner, Szubanski implied she feared it would not have been good for her career. "I love my work," she said, choking up with emotion. "The thing is, you're forced into this position where you almost feel like you have to choose.

"I know you're going to ask would it have been hard. Of course it would have. It's so recent that things have changed. In my lifetime, in my adult lifetime [homosexuality] was illegal. Doors would be bashed down and they would be taken and prosecuted."

Szubanski said any public perception that things were fine for gay people now was misguided. "There's a kind of velvet oppression going on. Younger people are killing themselves. It's not fine. This is a serious issue."

Her self-outing came the day after a Galaxy poll showed support for same-sex marriage in Australia at 62 per cent, with 81 per cent of people aged 18 to 24 backing it.

Asked by panellist Steve Price why the marriage issue was so important to the gay community she replied, "It's ironic that you represent the minority opinion but you're getting me to justify my life and love interests".

Undeterred, Price raised the prospect that gay couples might demand the right to be married in a church. "Society is not one fixed thing, it's a consensus that we all form," Szubanski responded.

"The bottom line is there's nothing wrong with being gay. I tell you, if there was a tablet you could take to cure it, I wouldn't take it."

Society would be much better advised, she said, to "look at the genetic predisposition for prejudice and intolerance, find a pill that will cure that, [and] put it in the water, problem solved".

Karl Quinn is on Twitter: @karlkwin