The story seems almost tailor-made for opera, and now the music-theatre work Watershed: the Death of Dr Duncan, is about to be staged at the Sydney Opera House.

It’s an ensemble oratorio created by composer Joe Twist, director Neil Armfield, librettists Christos Tsiolkas and Alana Valentine and historical consultant Tim Reeves, working with performers.

Watershed first took the stage at the Adelaide Festival in 2022 with tenor Mark Oates creating the double roles of Dr Duncan and SA Premier Don Dunstan. He will reprise the roles. 

I caught up with Oates by phone to Adelaide and found that this will be his Opera House debut.

Works like this don’t happen overnight, he tells me.

Oates joined the team for an intensive period of work with all the major players and the Adelaide Chamber Singers, who premiered the work, although in Sydney their role will be performed by the Opera Australia Chorus.

The process, he says, involved high emotion and a lot of pressure, learning new songs every day and discarding many by the way. They eventually presented a version of the work at the Elder Hall to 100 potential donors.

“At the end, Neil offered me the role and I promptly burst into tears in front of the sponsors.”

No stranger to working on original compositions, he had previously found there was often disappointment at the end when he was told he wasn’t going to get the role.

“But,” he says, “ I found I could discipline myself to enjoy the creative process for itself.”

Oates has been a long-term chorister and sometimes principal artist with the State Opera of South Australia for 30 years, generally playing character roles such as Basilio in The Marriage of Figaro or John Styx in Orpheus in the Underworld, so is considered “a crossover, a character tenor with a bit of a musical theatre sensibility”. Facing two major roles now, he’s thankful that when he studied, Elder offered courses in stagecraft and acting.

At 56, which he thinks is a good age for a tenor, Oates says he’s enjoyed “a beautiful purple path” in opera over the last few years.

“I did have a day job for some time, balanced with raising kids and buying a house, but for the last five years I’ve been a freelance professional artist,” he says. 

Joe Twist has written Watershed as an oratorio, with solos supported by choral pieces that move the plot along. Very much like Bach. 

The soloists represent events, while the choral pieces critique the social mores of the times and well-documented events, such as the history of gay predation.

“It was an awful time for the gay community,” Oates says, in understatement.

Oratorio it may be and Twist has published a version just for choirs, but through Armfield’s vision, he says, it’s been given a real sense of drama, so that it’s not just him as Duncan/Dunstan singing, but it’s also the dancer and the spectacular settings, with the river in the foreground and projections of the River Torrens on the backcloth.

“Rather than being just about the music, you are presented with this phenomenal visual feat that engages the senses and hyphenates the beautiful music – that’s what Neil’s done, with Alana and Christos.”

Likening one moment to Romeo Castellucci’s staging of Mozart’s Requiem at Aix-en-Provence, he says “One scene is quite extraordinary, with the dancer on the wire being flung out over the audience in a vivid depiction of a gay bashing… moments like that are to die for on stage.”

And the high point? Probably right at the end where the lyrics turn to the question of love, finishing with the unlikely definition which Oates loves – “love is a cheesy melt”.

Watershed, Joan Sutherland Theatre, Sydney Opera House, June 14-16.