The musical, by Jason Robert Brown, tells the story of writer Jamie (Findlay) and actress Cathy (de Jager) from two different perspectives - his, from the beginning of their relationship to its end, and hers, from the end to the beginning.

It's being presented by Dramatic Productions, directed by Richard Block, at Teatro Vivaldi from Friday. From April 30, the actors will be replaced by Mathew Chardon O'Dea and Josie Dunham. Block double-cast the show to give more actors a chance (and to ensure a replacement was available if one of the cast was indisposed).

De Jager brought the show to Block and suggested he produce it with his new theatre company. She said, "I'm obsessed with this show, really, really obsessed ... it's got such a great story and such original music."

She said she wasn't really like the insecure Cathy who relied on Jamie to be her rock, supporting her through the rejections she experienced as a performer, but identified more with the confident, successful Jamie. Findlay, on the other hand, studied acting in New York - where Brown's musicals, including this one, are often performed - and understood all too well the frustrations of the performing life.

"I'm probably the diva of the two of us," he said.

De Jager said the characters somewhat defied gender stereotypes: Jamie was the more honest of the two, wanting to talk about their issues, while Cathy tended to keep things to herself.

Findlay said he met de Jager at the audition but they clicked almost immediately and had enjoyed working together to develop the characters and their relationship.

Both said it was important to note that Jamie and Cathy each had strengths and weaknesses and the format of the show enabled the audience to see and understand both their perspectives - and, perhaps, to see aspects of themselves in the characters.

"They both do completely wrong things in the relationship," De Jager said.

The Last Five Years is on at Teatro Vivaldi, ANU Arts Centre from April 24 to May 2. Bookings: 6257 2718 or stagecenta.com.au.