His Glee days might be over, but Kevin McHale has found another musical classroom, in new movie The Choir.

When lively school choir teacher Wooly bounds onto the screen to encourage his troubled-yet-talented singing protege in The Choir, it's hard not to do a double take. Artie from Glee has grown up. Only now, he's swapped places, and is leading the class.

"I know, I'm not really going far on, am I?" says actor Kevin McHale, laughing. "I'm just getting old, that's what it is. I can't play the kid any more."

Playing "the kid" in Glee, however, put McHale on the showbiz map - the same goes for most of the young stars of the hit TV show - and after six years playing Artie, the door's wide open for other projects.

But the 27-year-old admits he found it hard to shake off mental images of his former Glee singing mentor Mr Schuester, while getting into character as Wooly. "I constantly kept thinking of Mr Schu from Glee. I was putting on my clothes and I was like, 'What would he do in this scene?' And then I was like, 'I can't do that...'

"I immediately wanted to speak like him, because I was used to seeing Matthew Morrison play that character [the singing coach] for six years."

The film focuses on Stet (played by 12-year-old Garrett Wareing), an angry kid with a beautiful voice, whose alcoholic mother dies in a car crash and rich father doesn't want anything to do with him.

He ends up at a fancy private choir school, based on The American Boychoir School, where Master Carvelle (Dustin Hoffman) and his right-hand man Drake (Eddie Izzard) become frustrated at his lack of discipline or formal musical training. Wooly, meanwhile, "sees his gift" and tries to give Stet a chance, "as he tries to navigate a world of crazy kids".

By crazy, McHale means competitive, talented and vicious - especially little Eddie Izzard lookalike Devon, who has always been the best singer in the school and will stop at nothing to keep Stet from taking that crown.

Exploring the bullying issue was one of the things that attracted Texas-born McHale to the script. "We all know how vicious kids can be. But especially in that sort of world, where they're on their own in the school, and it's all about the music and gunning for the top position. I really liked exposing all of that.

"You see the gross underbelly of that world, which I didn't even know existed. I didn't know these schools existed, I knew nothing about it," he adds.

Working with Hoffman was another attraction - though McHale admits, with a slightly sheepish giggle, that he was perhaps slightly too star-struck.

"It was so surreal. I think through the entirety of filming, I still felt it was surreal," he recalls. "I never quite got used to it, which is maybe not the most professional thing, but he's a legend, and I think he probably knows that."

He was also anxious about impressing comedian Izzard, admitting to being a little intimidated: "I was terrified they'd ask me to improv' in a scene with him."

Luckily, that didn't happen - they stuck to the script - and Izzard turned out to be, in McHale's words, "a brilliant, brilliant guy".

"I got to spend probably the most time with him, because we had very similar shooting schedules, and were staying at the same places, and he's just - he speaks a billion different languages, and he just needs to be in some form of government." (A billion may be an exaggeration, but Izzard performs comedy in English, Arabic, German, Spanish and French.)

The shooting schedule was punishing too, as filming for The Choir - which took place in Connecticut and New York - coincided with final scenes for the last season of Glee, which was shot in Los Angeles.

"That ended up being a bit of a challenge, because I wasn't supposed to be shooting them at the same time," says McHale. "So I was basically going from one set, to the plane, to the other set, and not really sleeping. I didn't sleep well for about six weeks.

"And before that I was actually here [in the UK], for this other show I'm doing, so I was never home."

That "other show" is E4's comedy panel game show Virtually Famous, which McHale hosts. Series two finished in June, and another is on the way.

It's quite a departure from school choirs.

"I love it," he says. "It's something I never thought I would do, and I'm probably not very good at it, but I really enjoy doing it."

Virtually Famous has also given him the chance to work in the UK, which he loves: "I feel like British people are always surprised when I say that. They think I'm just doing it to appease them."

He insists he actually prefers working with Brits, however, rather than Hollywood types. "Everybody's just so nice, and so normal, as opposed to in LA, people can get egomaniacal and things," he adds. "So it's refreshing to work with normal people."

He's starting to adjust to the fact Glee's come to an end, after six years of wheelchair-dancing and pop mash-ups. "I've gotten used to it now. That's probably the weird part... I couldn't imagine being used to that.

"But I do miss it. I miss seeing everyone, and I miss playing the part. But we had a really good run, and I think it was the natural time for it to end," McHale continues. "It was such a huge part of my life."

The Choir is released in cinemas on Friday, July 10