Phoebe plays Ryan's wife, Justine and is joined by Matt Nable who, as well as directing, will play a character called Johnny.
Filming began in Sydney this week and the film is due to premiere in 2022.
After making a name for herself overseas with The Vampire Diaries and subsequent spin-off The Originals former H20:Just Add Water, Phoebe, returned home to star in Aussie series Safe Harbour and Bloom.
Speaking to TV WEEK the 31-year-old admitted she believed it was some of her best work yet.
"I think people in Australia will get to see me in a different light," Phoebe said.
"I think everyone pigeonholed me as a sort of kid actor. But I've finally been able to do things, sign onto things I believe in, that challenge me and that have brought me to places I want to go."
WATCH BELOW: Bloom season two trailer