Sing star Matthew McConaughey on his worst audition

Matthew McConaughey has revealed how he once would not take no for an answer at an audition.

"I've had quite a few that didn't go well at all," the Oscar-winning actor told the BBC.

"Once I left the audition and pulled a U-turn on the highway 30 minutes later and returned and barged through the door to say: 'No - I'm doing that again!' - here we go'.

"I didn't get that job."

McConaughey was speaking in London to promote his new animated film, Sing, in which he plays a theatre-owning koala called Buster Moon.

In an attempt to avoid financial ruin, Buster holds a singing competition that attracts hundreds to the X Factor-style audition.

"There's nothing worse than leaving an audition thinking: 'I didn't quite go all the way'," McConaughey added. "That's hard to sleep with."

The Texas-born actor, who won an Oscar for Dallas Buyers Club in 2014, spoke more about his move into voice acting, his mining industry thriller Gold and his forthcoming role in The Dark Tower.

Matthew McConaughey with his animated character Buster Moon

Buster Moon is a koala with such infectious optimism. How easy was it to portray that with only your voice to act with?

"I changed my voice for it. Buster Moon ends everything on an up note.

"I gave it a punt and went in there and luckily the producers and director liked the angle I had."

You sing a little in the film - did you regret not getting to sing more?

"I didn't sing at all in the original script. And then one day the director Garth Jennings said we had this idea that you sing Call Me Maybe by Carly Rae Jepson when you are teaching the Scarlett Johansson character [a punky porcupine called Ash]. He asked: 'Are you up for that?' And I said: 'Yes absolutely - press record'."

Buster Moon and his devoted employee Miss Crawly (voiced by Garth Jennings)

You've done two animated films in the the past year - Sing and Kubo and the Two Strings. What have you enjoyed about your move into voice work?

"Now I have something that the kids can see. If you look at my films over the last 10 years I haven't made many that eight, seven and four-year-olds can see.

"It's really fun to do. With both of these I was thinking like an eight-year-old. There's something really unpretentious about it and I hope to do more."

The Sing voice cast includes Reese Witherspoon, Seth MacFarlane and Scarlett Johansson

Can you be more relaxed behind the microphone?

"Let's sing this line, let's say this line, let's yell this line, let's whisper this line - let's try it every way possible. And if you screw up so what? Plus, you can come to work in your pyjamas or a three-piece suit if you like."

Buster Moon and Gold's Kenny Wells share an ability bounce back when they are at rock bottom. How much did you appreciate those parallels?

"They are vastly different characters but both of them are salesmen and both of them are arguably delusionally optimistic. Both of them have nine lives. Both of them are down when they should be out. Both of them pull off great feats when the rest of the world says there's no way that can happen."

Matthew McConaughey as Kenny Wells in Gold with co-star Bryce Dallas Howard

We'll be seeing you next in The Dark Tower, based on the Stephen King book. What can fans expect from your role as sorcerer Walter Padick?

"Walter is not the devil but he does fancy himself as such. There are so many ways to be evil. You can do bad things or, as Walter does, expose hypocrisies and let them sink themselves.

"It's a plum role in a wonderful story of multiple worlds. I'm really looking forward to this coming out and I hope we'll be able to do quite a few."

Your True Detective co-star Woody Harrelson has just broadcast his film Lost in London live to cinemas. How mad was he to have done that?

"He's mad anyway. That's what's so wonderful about him. The man is married to adolescence and will never get a divorce, but he's one of the true great wild men in our time. I'm proud of him.

"He took on a great challenge with that and I'm glad he pulled it off."

And it has a joke in it about you.

"Yeah, I saw that - he and Owen Wilson saying: 'Matthew McConaughey doesn't want to see a picture of him looking fat' - but if you go and see Gold you'll see I'm quite fat in that!"

Sing is out on Friday 27 January and Gold is out on 3 February.