Matthew McConaughey with Camila Alves and his mother Kay. 

This might explain why Matthew McConaughey is the way he is.

In her new book, I Amaze Myself! (iamazemyself.com), Matthew’s mother, Kay McConaughey dishes on everything from her son Matthew’s conception to how her husband died in a compromising position with her!

“On Monday mornings, he and I often said goodbye by making love,” Kay, 77, says. “But one day, all of a sudden, it just happened.

“I knew that something was wrong, because I didn’t hear anything from him. Just nothing,” she says. “But it was just the best way to go!”

And when her man couldn’t be revived, she made sure he was taken from the house in the buff.  Yes, dead and naked!!!

“I was just so proud to show off my big old Jim McConaughey — and his gift,” she says.

Kay says, “I would love to be on Oprah!”

Anyone promoting a book wants to be on Oprah. Duh!

She also says that Matthew, 38, was a “happy accident.”

It was just after she’d married Matthew’s dad for the third time.

“I was deciding, ‘Do I want to have another baby? Do I want to have an affair? Or go back to school?’” she says. “That’s when Matthew was conceived. We had tried for 16 years and no baby. So Matthew was a big surprise!”

Kay is very…open about her personal life.  Wow!!!