Whilst promoting the release of his new book ‘Greenlights’, Matthew McConaughey answered questions from People magazine. The actor took this opportunity to reveal how his father, James Donald McConaughey, died back in 1992.On that fateful day, the young man remembers receiving a call from his mother to tell him the bad news. Matthew McConaughey recalled his reaction:My knees buckled. I couldn't believe it. He was my dad. Nobody or nothing could kill him. Except mom.And somehow he was right. James Donald McConaughey died from a heart attack while he was in the middle of having sex with his wife, Matthew’s mother.The American actor shared in People magazine that:‘He'd always told me and my brothers, ‘Boys, when I go, I'm gonna be makin' love to your mother’. And that’s what happened. He had a heart attack when he climaxed.’ Matthew McConaughey also used this interview to talk, at length, about his parents in general, who were unlike any other couple it seems.'They were divorced twice, married three times, I mean, yeah, it was like the Pacific Ocean in a storm,’ he explained, adding that they could even be 'violent’ with each other at times. This revelation is quite astonishing but one that he will undoubtedly tell his three children later on in life!