MAGDA Szubanski broke one of the entertainment world's worst-kept secrets last night when she came out on national television.

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".