Lena Dunham has compared rising star Bella Ramsey to Tilda Swinton.

The 'Girls' creator has adapted Karen Cushman's 1994 novel 'Catherine, Called Birdy' for the big screen, and Bella, 18, stars in the titular role in the medieval comedy, and has been tipped for a huge career by her director.

Speaking to HeyUGuys.com, Lena, 36, said: "The nearest I can compare her to is like a Tilda Swinton.

"Her range is wild and her ability to play with convention, I just think she has a very exciting career head of her and I feel lucky I was able to be there towards the beginning."

Joe Alwyn, 31, plays her Uncle George in the flick, and Bella recently explained that being "shy and awkward" around each other actually set them up well for filming.

She said: "We’re both quite shy. When we met each other, we were a bit awkward. I think that actually set us up really well. Birdy and Uncle George just get each other in a way that me and Joe do. He’s just so gentle and sincere. I felt very safe with him."

Bella is known for having played Lyanna Mormont in 'Game of Thrones' between 2016 and 2019, and also starred in the title role of Mildred Hubble in CBBC show 'The Worst Witch' from 2017 until 2019.

Meanwhile, Lena revealed that she never had anyone in mind for the role other than Joe.

She said: "He’s the only person I asked to do the part. Uncle George is the hunk in Birdy’s life who she sees in this idealised way. He’s never afraid to go to a strange or different place with the work."

'Catherine, Called Birdy' tells the story of a young woman whose father is financially destitute and attempts to marry her off to a wealthy suitor but she defies his plans.

The film - which also stars Andrew Scott and Billie Piper - will be available to stream on Prime Video from October 7, following a limited theatrical release.