That's further proof that The King, played by drag king BustHerr, is not toiling in a 7-Eleven as Slurpees revive the parched, and the fight for marriage equality is very much alive as the sideburned sex symbol performed mock wedding ceremonies in the Little Ole White Chapel at the Midsumma Festival.

For the first time in the festival's 29-year history, the theme is marriage equality, and lobby group Equal Love arranged the illegal exchange of vows by Las Vegas-style celebrants Marilyn Monroe, Elvis Presley, Cher and Liza Minnelli.

Equal Love campaign manager Anthony Wallace said Midsumma had always been apolitical about same-sex marriage but it had "come out" and demanded an amendment to the Marriage Act.

With Prime Minister Malcolm Turnbull committing to a plebiscite after the next election, Mr Wallace said the cause was worse off under the new PM.

"There is no free vote and if the lower house passed the amendment, marriage equality could be achieved within a week," he said.

Mr Wallace, surrounded by fake marriage certificates, veils, a cake and Monroe's bosom-inflated white dress, was concerned that a plebiscite would cost $150 million, there was no timeframe for change and did not mean the law would be amended. "It is not binding and it's costly to tell us what we already know."

Midsumma's new chairman, John Caldwell, said he supported equality in general. "I feel it's embarrassing that we, as a nation, are still having to talk about marriage equality. In my opinion this is a basic right for us all," he said.

"We will continue to inspire inclusion and to strive for social equality post marriage equality. We won't rest until every GLBTIQ child feels safe in every school, every employee in every workplace and every every person is safe on the street."

Up to 100,000 diverse people were expected to attend the Midsumma Carnival in the Alexandra Gardens, the opening event of the Midsumma Festival, which runs from January 17 to February 7.

It appeared Bunnings had been cleared of picnic chairs, beach umbrellas and Eskies as party-goers made themselves comfy on the lawn and under shady trees. The must-have inflatable toy for summer, the flamingo, also turned up among the blow-up couches and doughnuts.

A gay and lesbian party presents a delicious juxtaposition of imagery. Pretty boys paraded their torsos and packages in skimpy undies, ravenous folk queued for The Kaiser's Sausages and the 69ers Tenpin Bowling League dreamt of strikes and shiny balls.

Labor and Liberal Party members touted for voters at adjacent stalls, Victoria Police was recruiting and the Australian Federal Police gave away rubber rainbow bracelets.

Drag queens in summer frocks juggled a parasol with a fan and one poor dear had to ditch her mile-high stilettos for flats.

Essendon Football Club supporter group the Purple Bombers also had a stall and the only substances supplied for a hot day were water and 30-plus sunscreen.

Labor MP Jaala Pulford joined the formalities on stage with Lord Mayor Robert Doyle,  and  the lord mayor's wife, Emma Page Campbell, judged the much-loved dog show.

To resonate with the specific wiring of generation Y's brain, Equal Love sold $10 tote bags saying: "Totes for marriage equality."

The festival has appointed two "champions" and they are transgender performer Carlotta and former David Jones chief executive, Paul Zahra

Mr Zahra, the director of PwC's Diversity and Inclusion Advisory Board, said he was the first openly gay  chief executive of the ASX 200 – Australia's top companies – and more needed to be done to get a diverse board in corporate life.

"Anyone that's in a minority group needs to step up and take a leadership stand and make a difference," Mr Zahra said. "Having a diverse workforce means you get better decision-making."

Mr Zahra will speak about being gay in the corporate world on January 18 at Campari House.

The Midsumma Carnival is a dress rehearsal for the Pride March in Fitzroy Street, St Kilda, on January 31 and its theme is also marriage equality. Leading the procession will be Premier Daniel Andrews and Minister for Equality Martin Foley.

Seeing that the march will be celebrating its 21st birthday, there could be a few interesting birthday suits.