Phoebe Dynevor is to star alongside Zac Efron in 'Famous'.

The 29-year-old actress has boarded the cast of the Los Angeles-set thriller from director Jody Hill that explores the dark side of celebrity.

'Famous' stars Efron in dual roles as overenthusiastic fan Lance Dunkquist and Hollywood heartthrob James Jansen although Dynevor's part is yet to be revealed.

A synopsis reads: "Lance Dunkquist has one asset that's about to change his life – he has the face of a movie star. And not just any movie star – Lance is the spitting image of Hollywood icon, James Jansen. Lance is about to travel to Los Angeles to make his dream come true. Lance is going to be famous, no matter what it takes..."

The flick is based on the acclaimed novel by Blake Crouch and has been adapted for the screen by Chad Hodge.

Phoebe's casting comes after she lamented the lack of parts for actresses in her age range earlier this year.

The 'Bridgerton' star told the Evening Standard newspaper: "I have read some great scripts recently. And yeah, I probably shouldn’t be saying this, but there is still, like, not that many parts going.

"There is such a space for male actors ... there are so many of them. And they’re all great.

"They’re all very talented young men, and they do not stop working, and good for them.

"But you know, when I think about the girls my age ... there’s way more room for them and there is still not enough room for us.

"It’s a really good time for older women, which is amazing, and there’s a lot for these young men, but not a lot for the actresses that I know in my age bracket."