Elle Fanning learned ''how to be a woman'' through making 'Mary Shelley'.

The 20-year-old actress portrays the 'Frankenstein' author in the new biopic from Haifaa Al-Mansour and though the precocious writer lived in the 19th century, Elle promised the tale - which documents Mary's tumultuous romance with the poet Percy Shelley (Douglas Booth) - still feels ''timely and modern''.

She said: ''I felt like I learned a lot from Mary about how to be a woman.

''I felt like I took her life on and experienced it all from beginning to end from her, which was exciting.

''The movie is very... it's a period piece but it's also very timely and modern.''

Elle hailed the movie as a ''milestone'', not only because she learned a lot and related to the character as an artist, but because it marked her move into adult life.

She said:'' What fascinated me about the script was that it's about a struggling artist, but it's a woman struggling artist, which you don't see very often.

''When I filmed the movie, I was 17, about to turn 18.

''This was the last movie that I had to do school on the set. It was a milestone movie for me.

''I really felt wiser and more mature after.''

The actress hailed the author as a ''feminist icon'' and feels she's often overlooked in discussions about classic authors.

She told Total Film magazine: ''I remember talking about Mary Shelley in school but just Lake Geneva and Lord Byron and that story. It's true but it's not the most interesting thing about her.

''She's a feminist icon, but most people don't hold her in the same regard as, say, Jane Austin.

''She's just very interesting and not given the credit that she deserves.''