Eddie Redmayne doesn't want to let J.K Rowling down.

The 34-year-old actor - who stars as magizoologist Newt Scamander in 'Fantastic Beasts and Where to Find Them' - admits he is feeling the pressure of being part of the project and desperately wants to impress the author.

He said: ''It's J.K Rowling's world and I think she's a genius. I love everything that she's done.

''And now I'm getting to enter it; I don't want to be the one who lets that down. I'm not the sort of person who can go, 'This one's for fun!' But I am trying to learn to enjoy it.''

The film - which is set in 1926 - sees Newt stop in New York after a successful mission to hunt down magical creatures. But things don't go quite to plan when his magical case goes missing and the fantastic beasts escape.

Speaking about the film's concept, he added: ''Certainly some of the themes are more adult. There is a darkness to it, there are comedic elements to it, there's a romantic side to it, there's a thriller quality and yet at the end, when I saw the final cut, I was deeply moved by it.''

And Redmayne is ready for his character to soon be immortalised in merchandise and admits he already has his own Newt figure.

He told the i newspaper: ''We've got him but he doesn't have freckles, so my wife painted freckles on him. One can be cynical [but] as a kid growing up... I flippin' loved [the 1980s cartoon] Thundercats! I wanted every single toy! They gave me so much pleasure.''