Tina Arena used a biblical analogy speaking for the first time about her ex-husband Ralph Carr since he was convicted of rape.

“You reap what you sow, so now he’s reaping what he sowed,” the acclaimed singer said on Wednesday night at the Melbourne premiere of a documentary about her life. “I believe that justice has been done, and the right thing has happened.”

At the premiere of Tina Arena: Unravel Me at Melbourne International Film Festival, she addressed the issue in an on-stage Q&A after the screening.

High-profile entertainment manager Carr was convicted in July of one count of sexual assault and two counts of rape. A suppression order protecting his identity was lifted last week. Until last month, he represented former Richmond player and Brownlow medallist Dustin Martin, and in the past has counted musicians including Kate Ceberano, Vanessa Amorosi and Deborah Conway as clients.

Carr is currently awaiting sentencing; his lawyers say he will appeal the verdict.

Although she doesn’t know the victim, Arena expressed support and respect for her bravery in speaking out. “I don’t know her name, I have never met her [but] my heart goes out to her, to her mum, her family, for having the unbelievable courage to come forward in unbelievably complicated circumstances,” the 58-year-old said.

“So first and foremost a big thank you to you, whoever you are darling, wherever you are, a big thank you, not only from me but a big thank you from a lot of people.”

Speaking to the Hollywood Reporter ahead of the screening at The Astor Theatre in St Kilda, Arena said, “a big part of this documentary was to celebrate 50 years of surviving in a very difficult industry”.

“But it was also the right moment to really be able to open up and to talk about things and stories that people don’t really have any idea of,” she continued.

“I wanted those stories to come from me because they’re my words, they’re my experiences, and they are not interpreted through somebody else’s eyes – they are conveyed through mine. And that was a really important exercise for me, I wanted everyone to hear it from my mouth.”

Arena and Carr married in 1995 and divorced four years later. In the documentary, Arena recalls in 1997, having released her highest-charting single Burn, “the emotional side of me started to collapse”.

“I’d realised there was no one burning for me,” she said. “My opinion didn’t count. It was like, ‘You don’t know what you’re talking about’. You’re purposely kept on a treadmill because once a cash cow, always a cash cow.”

Speaking to this masthead last month, the acclaimed singer was asked about the line that stayed with her. “Be careful who you surround yourself with,” she replied. “It was probably John Young [host of Young Talent Time, on which Arena appeared as a child] who said that to me. He’s very much like a father figure; he wanted me to be as protected as I possibly could. There were times when he said, “Be careful, I don’t like that person” – and he was right. He taught me about discernment as a very little girl. I wasn’t able to intellectualise the term back then, but it became much clearer down the track.”

Arena announced on Thursday that she would take part in a conversation with Mary Coustas at preview screenings of the documentary in Sydney on August 23, ahead of the film’s national release on August 27.