James McAvoy is dishing behind-the-scenes details about the upcoming film "X-Men: Days of Future Past."

McAvoy explained to an XFM radio station how he felt on his first day on the "X-Men" set. Though he'd work with some of the original "X-Men" cast members on other films, he found himself feeling nervous.

'Although I'd previously played Charles in one other movie, it still did feel like I was being initiated and that there was a baton being handed over," McAvoy told XFM. "It was a very kind of ceremonial scene, in a very sort of ceremonial location. We were in a monastery, and the set was very quiet, and the director made sure that... It was much more like a sex scene."

''You know that when we do sex scenes we make sure there's nobody on set. It's just the boom operator, the camera man, and you don't have loads of people staring at you... usually we do," he continued. ''And it was a bit more like that. Clearing the set, making it very quiet, very reverent, that was kind of cool. It felt like I was being initiated into some kind of superhero sect!''

"X-Men: Days of Future" past will be released to theaters on May 23. Check out the trailer for the film below.

In other "X-Men" news, writer Simon Kinberg confirmed Quicksilver will be appearing in "X-Men: Apocalypse." The writer also spoke to Total Film about the backlash the film faced over introducing Quicksilver to the franchise.

"It wasn't something we anticipated because we didn't know they were using him in the 'Avengers' movie. We only found that out...weeks after we made the decision that we had done it. And then, after that even, I think it was a little while before the controversy started," Kinberg told Total Film.