US actress Elle Fanning attended the premiere of Ginger & Rosa, about two friends growing up in 1960s London.
The 14-year-old confessed her audition for the role was daunting.
"I was so nervous. I had to audition in front of Sally (Potter, director) who is from London, with an English accent, and I didn't want to mess up," she said.
"Afterwards, when I knew I had got the film I worked with a dialect coach and really got the accent as perfect as possible."
And Fanning revealed she loved the vintage costumes she wore in the film.
"We were beatniks and wore skinny jeans and we had a lot of fluffy sweaters - you guys call them jumpers - it was fun to try it out," she said.