Livvy was Australia's sweetheart in the '70s and '80s, and Delta, 33, took on that mantle when her career took off a couple of decades later. It would be hard to find a better fit.
Young Olivia Newton-John played by Morgan Griffin
Depicting ONJ in her early years is an Australian actress who knows a thing or two about starting early. Twenty-five-year-old Morgan Griffin starred in the second season of The Sleepover Club as a teenager.
John Travolta played by George Xanthis
You need a certain amount of swagger to pull off Grease-era John Travolta, and George Xanthis brings that and then some. Before Olivia, you might have seen him in SBS series The Principal and Deep Water.
Matt Lattanzi played by Richard Brancatisano
Olivia met her first husband—the father of daughter Chloe—on the set of Xanadu. He's depicted by an actor born three years after that musical came out: 34-year-old Richard Brancatisano, who you might recognise from Underbelly: Razor or short-lived 2013 series Reef Doctors.
Lee Kramer played by Todd Lasance
Look at that hair! Ex-Home and Away regular Todd Lasance, 33, gets his '70s on to play Olivia's one-time manager and boyfriend, Lee Kramer.
Pat Carroll played by Georgia Flood (age 16-22) and Kate Jenkinson (age 22 onwards)
Two young Aussie actresses portray ONJ's former singing partner and lifetime friend. Georgia Flood, who played Bea Smith's daughter on Wentworth, handles the early years, while fellow Wentworth star Kate Jenkinson, 36, assumes the role later in the miniseries.
Bruce Welch played by Hugo Johnstone-Burt
In real life, he was a member of Cliff Richard's band, The Shadows, and at one time engaged to Olivia; in the show, Welch is played by The Wrong Girl's Hugo Johnstone-Burt.
Roger Davies played by Gyton Grantley
He took over as Olivia's manager in the late '70s, and has steered the careers of Cher, Pink and Tina Turner for decades. In Olivia: Hopelessly Devoted to You, showbiz supremo Roger Davies is depicted by House Husbands and Underbelly star Gyton Grantley, 37.
Johnny O’Keefe played by Sam Duncan
Like ONJ, Johnny "The Wild One" O'Keefe is an Australian performer known by just three letters. Playing JOK in the miniseries is relative newcomer Sam Duncan.