Saoirse Ronan has revealed she will not be playing woodland elf Itaril in The Hobbit.

The Hanna star had been in talks to star in The Lord Of The Rings prequel, directed by Peter Jackson, who she worked with on The Lovely Bones, but has now signed up to star in The Host.

Saoirse revealed: "It's probably not going to work out with The Hobbit unfortunately.

"Because I would have been working for about a year on it and there were other projects that I was very interested in, but Pete and [his producer wife] Fran have been very good about it and very understanding.

"I'll have to just go back down to New Zealand for a holiday and hang out with the hobbits."

Saoirse stars alongside Eric Banna, Cate Blanchett and Tom Hollander in Joe Wright's new action film Hanna, about a teenage girl who has been raised as a trained assassin and escapes to track down the woman who killed her mother.

Despite growing up on film sets, the 17-year-old actress said she didn't relate to Hanna's isolated life, but her journey of self-discovery.

Saoirse said: "I don't feel isolated on a film set. In a way you do because you don't really mix with the outside world you're just sort of working non-stop for a few months but you've got so many people around you.

"But one thing that I did find I identified with was the journey that she goes through. It's very similar to what a teenager would go through around my age. I turned 16 when I made the film and I feel like her journey is very much about growing up and finally breaking away from home."

:: Hanna is released on Friday May 6.