James McAvoy admires the ''dedication'' of Hollywood hunks like DWAYNE 'THE ROCK' JOHNSON, Hugh Jackman and Chris Hemsworth after he was required to get into action man shape for 'Glass'.

The 39-year-old actor hired personal trainer Magnus Lygdback - who oversaw Gal Gadot's regime for the sequel 'Wonder Woman 1984' and Alicia Vikander's exercises for 'Tomb Raider - to help him achieve the required physique for his role as multiple-personality sufferer Kevin Wendell Crumb as he knew he would be spending much of M. Night Shyamalan's movie with his shirt off.

After putting in so much hard work in the gym, McAvoy has nothing but respect for the leading men who have to be in that sort of condition for every movie they make.

In an interview with USA Today, he said: ''I was like, 'OK. I'm going to have my shirt off, aren't I?' And (Shyamalan) was like, 'Yep.'

''Guys like The Rock and Hugh Jackman and Chris Hemsworth - the guys who keep themselves in that condition every day. That dedication is incredible.''

One of Kevin's split personalities is the monstrous Beast and it was that dark, animal-like persona which required him to be in super shape.

He said: ''I knew I had to get down in the gym and kind of back up his name. I had to give a little bit of aesthetic credibility to that fear that he's supposed to inspire in people. You're in every day working your socks off (acting), and you're also in the gym at five in the morning and then pretty much working out on set whenever you are the Beast to get you all pumped up and get your veins popping and get the relevant muscles swollen for the shot.''

''He's not like a supervillain in most movies who is like, 'I look like I've got a six pack and I'm going to destroy the world!' He is not a megalomaniacal, despotic human. He is alien. He is animal. He is other than human. Just standing still as the Beast was tiring in a way that no other character is.''