In Kubo and the Two Strings Matthew Mcconaughey played the Beetle, and now he has the lead role as the koala Buster in the musical comedy Sing. And he discovered that he loves this kind of work.

"There's a real freedom to it that I look forward to taking back to my live-action acting," he says. "There's no self-consciousness whatsoever, because there's not a visual. You can wear shades and a hat and pyjamas if you want!" 

Buster judging in SingBuster judging in Sing

On the other hand, McConaughey had never sung professionally. His costar Reese Witherspoon has more experience, having won an Oscar playing June Carter Cash in Walk the Line. For her, the challenge was performing a new kind of music. "The country music was much easier for me," she laughs. "Singing Taylor Swift's Shake It Off is really hard! And I happened to have run into her while I was making the movie, and I was like, 'I have a new appreciation for how hard you work.' She's like, 'Yeah! I work really hard.' And then my kids had to endure me singing Firework around the house 400 million times. So they were happy to see the end result."

Witherspoon also found resonance in her character Rosita, a pig housewife. "She's had 25 kids, so she had to put her dreams on hold, and now the singing competition gets her out of the house and remembering that she had a life beyond having kids," Witherspoon says. "I think it's a really touching story. I think a lot of moms will relate to it, and I think a lot of kids will appreciate their mom more after seeing it."

For his next on-screen role, as a prospecting businessman in Gold, McConaughey had to gain quite a bit of weight. But he enjoyed the process. "My body felt great. I slept great. My back and knees, everything felt physiologically better," he says. "Mind you, if you lived on the diet for four years, you would feel lethargic. I figured it out: what makes you tired when you're overindulging is thinking about quitting. What makes you tired is looking in the mirror on Monday morning and going, 'You gotta clean yourself up, man.' I would wake up on Monday morning and go, 'Let's have another beer and cheeseburger!' I really never got tired of cheeseburgers, so it was more fun getting there than to lose it all."

Watch the trailer for Sing: