Matt Smith is to star in 'How to Catch a Monster'.

The 'Doctor Who' star has signed up for his first big screen acting role in 'Drive' actor Ryan Gosling's directing and screenwriting debut.

The dark fairytale also stars Christina Hendricks as single mother-of-two Billy who is swept into a macabre fantasy underworld after her teenage son Bones discovers a secret road leading to an underwater town.

Although it is unclear as to what character Matt - who recently finished filming his third series as the Time Lord in the BBC sci-fi series - will play at this time, Variety reports the British actor will take on a lead character.

Ryan's 38-year-old girlfriend, 'The Other Guys' actress Eva Mendes, has also been cast as an unspecified role.

Matt's casting has sparked rumours he is set to leave 'Doctor Who' but the BBC insist he is still committed to the role.

A Doctor Who spokesman said: 'As in previous years Matt is taking advantage of a gap in the 'Doctor Who' production schedule to take on another project. It's the 50th year of 'Doctor Who' and Matt is committed to the show. He will be around for a while yet.'

Production for 'How to Catch a Monster' is scheduled to begin in the spring.