James McAvoy changed how he played his character's split personalities in 'Glass' compared to 'Split'.

The 39-year-old actor reprises his role in 'Glass' as multiple-personality sufferer Kevin Wendell Crumb, who kidnaps three teenage girls in M. Night Shyamalan's 2016 psychological thriller 'Split' whilst moving towards becoming his darkest alter ego The Beast.

McAvoy portrays 21 different personalities in 'Glass' - which completes a trilogy which began with 2000's 'Unbreakable' - and for his return as Kevin he made sure he made each alter ego distinct to help the audience differentiate them all.

Speaking exclusively to BANG Showbiz at the 'Glass' UK premiere at the Curzon Mayfair in London on Wednesday night (09.01.18), he said: ''Patricia is probably my favourite in 'Split', in Glass its Hedwig. But it was important in this one to make sure the edges in each character was sharp so that the audience could tell if not exactly who I am at every moment, they could tell I was definitely someone else in that moment.''

The Scottish star also admitted that he ''spent a lot of time in front of the mirror'' while preparing for his multi-faceted role, which is a technique he hasn't applied since much earlier in his career.

He said: ''I just rehearse and rehearse and rehearse and spend a lot of time in front of the mirror which I haven't really done since my early 20's as an actor.''

McAvoy was joined on the red carpet by his co-stars Samuel L Jackson - who plays Elijah Price, also known by his pseudonym Mr. Glass, a comic art gallery owner from 'Unbreakable' - and Bruce Willis, who is back as security guard David Dunn who discovers he has super-human strength and resistance to injury in the 2000 original.