Catherine McGregor's life on stage

Heather Mitchell plays 62-year-old McGregor in Sydney Theatre Company's Still Point Turning: The Catherine McGregor Story.

This vivid theatrical portrayal of one of Australia's most intriguing public figures opens on April 21 and is based on real life interviews conducted with McGregor over the course of many months.

It covers McGregor's military, cricket and political career as well as the story of her transition.

From the age of eight, McGregor said she knew she was a woman. But first she would have to live as a man called Malcolm. She played many parts - son, brother, husband, athlete, soldier, speechwriter - working in professions full of machismo and inside institutions built by men.

Every day was a challenge which took its toll. In 2012, aged 56, McGregor faced a turning point - to end her own life or to begin living authentically by transitioning to life as a transgender woman.

Director Priscilla Jackman said 99 per cent of the words spoken on stage are McGregor's.

"She has trusted me, our team and STC as a company, to present, manage and give life to her story in a way that is full of integrity," she said.

"Catherine lived the life, she shared with me her extraordinary experiences and her words, giving me the opportunity to craft a new theatrical work from them, but she hasn't at any stage stepped in to manipulate or reshape the outcome. As Catherine puts it cricket - not theatre - is her game."

McGregor said it was "very humbling" to have this amount of interest in her life. "

"I still haven't processed it properly," she said. "It's been a joy working with Priscilla. She's treated me with great respect and sensitivity, which has been very moving. It's an incredible honour to have my story told on stage and I'm really touched by the passion that has gone into this project."

The role of McGregor will be played by three actors - trans actor Andrew Guy who plays Young Malcolm, Ashely Lyons who plays McGregor prior to transition, and Heather Mitchell - who plays McGregor now.

McGregor said she hopes the play will help humanise the experience of trans people and bring that to a wider audience.

"I hope if nothing else, sceptics who see the play will be privy to the suffering that's part of the process of making the decision to transition genders.

"If it actually gives people pause to think that's it's not a frivolous exercise, that we're not freaks, we're actually people who have suffered in our raw humanity before making this decision, I think we will have achieved something."