Matthew McConaughey consulted three doctors about HIV in his teens.
The 44-year-old actor - who plays AIDS sufferer Ron Woodroof in 'Dallas Buyers Club' - admits he was so concerned about the rise in the sexually-transmitted infection while he was growing up in the 1980s that he sought advice from a number of different health professionals.
He said: "I remember in 1988 I was a senior in college and as a heterosexual young man becoming sexually active I remembered getting worried and what I clearly remember is talking to three different doctors and saying, 'Give me some science on this. 'I'm a heterosexual man and I'm having . . . I'm not being too loose but give me some percentages, give me something . . . ' and they had three completely different answers about what the risks were so I came away from that being more scared.
"I remember thinking, well, I'm gonna go with the guy who said be the most cautious. But nobody knew at the time, the doctors didn't know."
The hunky star - who has children Levi, five, Vida, four, and Livingston, 17 months, with wife Camila Alves - also admits he was keen to steer away from making his role too soppy because that wasn't the aim of the movie.
He explained to RTÉ Ten : "This story hasn't been done this way, it hasn't been approached this way. This story couldn't have gone to sentiment especially in the third act but it would have been untrue to the man Ron Woodroof ... This is not a message movie. The message comes out of following this guy's life."