Matthew McConaughey talks lifelong dream of being a father and the first moment he saw his wife

Matthew McConaughey details everything from his lifelong goal of having children to his love for his wife in his new memoir, “Greenlights.”

During an appearance on “Good Morning America” on Monday, the Academy Award-winning actor spoke about spending 52 days in the desert going through his old journals to put together the memoir, out Oct. 20.

“I had been threatening to go away with these journals for the last 15 years but never had the courage to do it," he said.

"Finally, I got a little bit of time on my hands and a kick in the backside by my wife, which she does so well, and she said, 'Get out of here and don't come back home till you got something,'" he added. "And what I found was what you got in this book."

In the memoir, McConaughey, 50, writes about meeting some of his father's friends as a young boy and realizing he wanted to become a dad one day.

"I was meeting some of his new friends, looking up at them and shaking their hands, and saying, 'Nice to meet you, sir.'" he said. "In my 8-year-old mind, what I noticed at that time, was every man that I had said 'sir' to -- the common denominator was they were all fathers, and I remember saying, 'That's when you've made it. That's when you've succeeded in life, when you become a father.'"

"From that day on it was very clear to me the one thing I knew I always wanted to be," he added.

He now has three children with his wife Camila Alves McConaughey, Levi, 12, Vida, 10, and Livingston, 7.

McConaughey also wrote about his own father in his memoir and his home life growing up.

"He really instilled values in myself and my two brothers, values that I know I wouldn't be sitting here, the man I am with the life that I've got, if he wouldn't have worked to instill," he said.

Another highlight of the memoir? He shares more about the moment he first saw Alves, who he married in 2012.

"I can't say I knew she was the one," he said. "I will say this, she was moving to my right to left across a room, and it did not look like she was walking, meaning her head was not bobbing. She was more floating, and I did not say who is that -- I said what is that?"

"Every beautiful thing that went through my mind about who and what she was, she has turned out to be exactly that and then some," he continued. "I knew right away she was something special, and then very soon over the next years is when we really fell in love, and I knew this is the woman I want to spend the rest of my life with."