Eddie Redmayne doesn't know whether he will be in all five 'Fantastic Beasts' movies.

The 36-year-old actor starred as Newt Scamander in the 2016 'Harry Potter' spin-off and is set to reprise his role in the upcoming sequel, but recently J.K. Rowling - who penned the scripts for the new movies - revealed she hopes to write five movies in total.

But Redmayne admits that although Rowling's plans are ''pretty exciting'' he never knows whether he'll be returning as the Magizoologist.

He told Collider: ''The truth is, to be honest with you, whenever Jo [Rowling] comes to set, which was quite a lot more on 'Beasts' on the second one than on the first film, you will always see a crowd of actors surrounding her, desperately trying to eek out information about the characters. One of the wonderful things is that she responds to what she's seeing in the rushes and her sense of where the story is going, or what her interpretation of what the characters are. She will then respond to how actors are performing it, and that is a lovely thing. The answer is you get snip-its, but always with the sort of caveat that it could change. It's pretty exciting.''

The second of five adventures follows on from the end of the first film and sees the Dark wizard Gellert Grindelwald [Johnny Depp] escaping from the Magical Congress of the United States of America (MACUSA).

Now the wizard is gathering followers to raise pure-blood wizards up to rule over all non-magical beings.

In order to stop him and his plans, a young Dumbledore [Jude Law] enlists the help of Magizoologist Newt Scamander [Redmayne] who agrees to help, unaware of the dangers that lie ahead.

Lines are drawn as love and loyalty are tested even among friends and family.

Redmayne also said how shooting the sequel was a little longer than the first film and had nothing but praise for Rowling.

He said: ''I think it may have been ever so slightly longer. It's a most intricate script and she's woven these extraordinary threads that pull you back into the world of Potter and collect the beasts lore, the sort of Potter lore. What is amazing about working with Jo is that she does it because of how passionate she is about her characters.

''It oozes from every pore of her and you feel so inspired, basically, working on one of her pieces because you know how much she cares about every single character. That's a wonderful thing.''