But when the film version of Holding the Man, the 1995 memoir by Timothy Conigrave, screened for the first time this week, there was a whole new set of questions on the agenda.

Screenwriter Tommy Murphy, who adapted the book for stage 10 years ago, said the timing of the film, which screened at the Sydney Film Festival this week, was incredibly serendipitous.

"It takes such patience to make a feature film, and since I worked on the play version, I adapted that almost 10 years ago now, it does feel like a very different moment," he said.

"I was aware the play was going to its audience at a time that feels very different to now, and that's just an extraordinary accident"

Published in 1995, Holding the Man is a best-selling memoir that chronicles the 15-year relationship between Conigrave and the captain of the football team, John Caleo, beginning in 1976 and ending with both men dying of HIV-related illnesses.

Murphy, who is originally from Queanbeyan and went to school in Canberra, said the story was a heroic and personal account of an effort to achieve equality.

"But the timing of the story means that that chimes with the marriage equality debate in a way that we didn't anticipate and in a way that we didn't attempt, but it's just a strange accident of when the film arrived in front of its audience," he said.

The film stars Ryan Corr and Craig Stott, with an all-star cast including Guy Pearce, Anthony Lapaglia and Geoffrey Rush.

Murphy said he often thought about his real-life protagonists, and what they would think if they had seen the audience laughing in all the right places at what is actually a humorous and tender love story.

"In some ways the film is even more loyal to the book than the play… It's certainly loyal to the variety of emotions," he said.

"Tim Conigrave's book is very funny. It's remembered as a tragic romance, so I hope and last night's response I think confirmed, that we've made good use of Tim Conigrave's wit, so the audience laughed a lot."

But when Murphy adapted the story for the stage 10 years ago, there was a different conversation playing out in Australia, around society's treatment of HIV/AIDS.

"I think at that time we were coming out of what some people called a long silence, which is when HIV had slipped from visibility a little bit," he said.

"There's this whole different conversation about HIV now which is very hopeful and we think that by 2020 we might end new transmissions of HIV... And then obviously marriage equality is a very different conversation now."

Murphy said he and his long-term partner, Dane Crawford, were "as impatient as anyone" to see gay marriage brought into law in Australia.

"If this film contributes to that conversation that the country's having at the moment, then I'm glad that might happen," he said.

"There's a line from the book, that's also in the play and also in the film, where Tim kind of lets slip and says, 'Will you marry me?' He really says that, and it's sort of laughed away.

"But I think that line had a different emphasis, even though it's the same line. It had a different emphasis in the film than it did in the play. When Tim said it in the book he sort of laughed at it."

Holding the Man will be released nationally on August 27.