Back in primary school, Kate Jenkinson played Olivia Newton-John's Grease character Sandy in a concert.
"I think it's safe to say that Delta [Goodrem] will have done a much better job than I did when I was 12," she laughs.
"I know my limitations and I know getting myself into a black jumpsuit and singing is not my strong suit."
In Olivia Newton-John: Hopelessly Devoted To You, Kate plays Olivia's bestie, Pat Carroll.
"I've always thought Pat was Olivia's great love, because they were always together," Kate, 36, explains.
"I think that friendship is incredibly special to both of them.
"Obviously, so much is made of her famous relationships. But really, it was the woman in the wings that no-one really knew about who was her constant and her rock for so many years."
Pat and Olivia became friends during their teenage years. They formed a duo and sang at clubs in London.
"They performed a lot," Kate says.
"But then Olivia's star continued to rise and Pat got married – ironically enough, to John Farrar, who went on to write so many of Olivia's songs.
"I think Pat was pregnant at the time Olivia was doing Grease and her [Pat's] husband was actually the person who wrote 'Hopelessly Devoted To You'."
The two women later went into business together with their Koala Blue retail empire.
Wentworth star Kate says she didn't know Delta before shooting Olivia, but had "a blast" working with her.
"Every single morning in the trailer as we were getting made up, Delta would bless us with an amazing rendition of some incredible song," she says.
But Kate – who portrays the older Pat, while Georgia Flood plays the younger one – doesn't sing at all in the miniseries.
"I'm wondering if it's because the producers heard me sing and compared it to Delta and they're like, 'Maybe we'll just keep her quiet!'" the actress laughs.