Lily Collins says there is extra pressure with The Mortal Instruments: City of Bones because the books have such a large and loyal fan base.
The actress is set to play heroine Clary in the big screen adaptation of the books by Cassandra Clare.
The first film hasn't hit the big screen yet but Collins reveals that a second movie has already been given the go-ahead.
Speaking to the Press Association the actress said: "We've already been green lit for a second one which is really exciting, so we're prepping for the sequel.
"I believe in the stories, I believe in Clary the character, I love that fantasy world, I love playing in it. And the thing I love the most about these books and what Harold [Zwart] our director has done is he's brought it to this realness that really grounds it and doesn't make it just a fantasy film.
"It's got many, many fans which is a blessing because you have a built-in audience.
"Of course there's extra expectations but at the end of the day they've been so supportive and positive so far, so I do feel very positive that it's going to be received well. I'm very proud of it."
The Mortal Instruments: City of Bones is the first film for Harald Zwart since The Karate Kid and he has brought together a great cast that includes Lena Headey, Jonathan Rhys Meyers and Jamie Campbell Bower.
The Mortal Instruments: City of Bones is released 21st August.
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