Matthew McConaughey has told how he had to become outrageous cowboy Ron Woodroof for his role in The Dallas Buyers Club, Belfast Telegraph revealed.

The 44-year-old actor stars in the true story about a man diagnosed with HIV in the 80s and given 30 days to live. The film sees Ron illegally import drugs from other countries for HIV and Aids because of the lack of approved treatments in the US. He also becomes friends and business partner with a transgender man, played by Jared Leto.

Matthew told Empire magazine: "I just did my best to honour this guy. And when you get a role like this it's full-on immersion.

"It's an adventure and it's more than dressing up and playing Hallowe'en.

"It's 'don't act like the guy, BE the guy.'

"And you know Ron was a full-on blasphemous b*****d , an SOB - but you can't help but love him, and everyone knows someone like that."

The actor lost three stone for the role, and revealed people thought he was really ill.

He said: "Now and then I'd meet someone I hadn't seen for a while and they'd go, 'Oh my God, you're sick!' And I heard some people said, 'Oh, he's got some disease, so he's taking this role as a cover.' But I wasn't really engaging with any opinions from the outside world at that time anyway."