James McAvoy reveals he nearly died from 'botched' lung biopsy before transforming for 2019 film Glass

James McAvoy has shared that he almost died after his lungs collapsed amid a 'botched' medical procedure.

The 47-year-old actor, who claims a former co-star bullied him, was a guest on Dax Shepard's Armchair Expert podcast this week, where he discussed the 'crazy' health incident.

'I had a lung puncture… they saw a shadow in my lung, so they wanted to biopsy it to see if it was cancer, which it wasn't, which was great,' he recalled.

McAvoy said he was alone during the scary moment his vital organs gave way.

He continued: 'But that was botched, and I nearly died. I was at home two days later, and my lungs just collapsed in bed one night. And I was on my own as well, so it was crazy.'

The star detailed spending two to three weeks in the hospital as doctors unsuccessfully attempted to clear his lungs. 'They were like, 'We're going to need to cut you open big style, go in with, like, dish soap basically and just clean you out, scoop it all out,' he told Shepard.

McAvoy also spoke about getting in shape for the 2019 film Glass, the sequel to the 2016 psychological thriller Split, as he recovered from the medical crisis.

In the follow-up movie, he returned to play Kevin Wendell Crumb, a man with 24 personalities. 

However, he explained the role mostly called for him to portray The Beast.

The actor explained: 'Unlike [in] Split, I was The Beast [for] most of the movie, and I was just outside in broad daylight as well.

'So I was like, I'm really going to need to do the real thing. I'm going to need to go for it. I remember saying to [writer/director M. Night Shyamalan], 'You're going to need to get me a trainer.'

Shyamalan offered to set McAvoy up with a trainer at a local gym, but he said he wanted someone who could 'make me look like a Greek f**king figure from mythology.'

In the end, he said: 'The guy that worked me was amazing. For the first four weeks, he rehabilitated me. 

'I could walk, but I couldn't run, couldn't cycle, couldn't jog … so he did a lot of rehabilitation and, sort of, functional movement, and then put the pounds on me really fast.'

Also this week, McAvoy claimed that one of his Band Of Brothers co-stars bullied him while on set of the 2001 war drama miniseries.

The Scottish performer got candid about the incident during Monday's episode of Watch What Happens Live. 

He was asked by host Andy Cohen to rate his experience on a number of projects, and the HBO miniseries quickly came up.

'On my first day on set, there was like a ton of actors. It was one of those scenes with everybody in it, and we're at a bar,' he began.

McAvoy added, 'I had a scene and all these guys were in it for like nine months, 10 months, and they get one line in one episode, and one line 10 episodes later. And they were all pissed.'

The Atonement star continued, 'And I come in for one episode and I've got like an arc and scenes. I've got tons of lines. And so, one of the guys decided to bully me on my first day as a professional actor out of acting school.'

He alleged that the co-star, whom he did not name, 'got him and his buddies to stand, point and laugh at me for like, three minutes.'

Cohen interjected, 'That's terrible!'

McAvoy added that Dexter Fletcher and Robin Laing 'took me aside, they were like, 'Come hang with us man.''

McAvoy said the experience of working on the project was a nine out of 10, but the day he was allegedly bullied was a two.