Matthew McConaughey on His Lookalike Son Levi Following in His Footsteps (Exclusive)

Matthew McConaughey is a proud father when it comes to his his children with his wife, Camila Alves.

Matthew McConaughey is a proud father when it comes to his three children with his wife, Camila Alves. ET spoke with the actor about his new memoir, Greenlights, and he talked specifically about his eldest child, 12-year-old Levi, who recently made a rare appearance on Alves' Instagram and had his fans marveling at their similar looks.

"Levi is the most considerate person I've ever met," the actor tells ET's Rachel Smith. "Yeah, he's extremely considerate and a very, very sensitive young man and really cares -- really caring kid. And he, like me, has a very much perfectionist bone in him."

"He wants things to be exactly how he wants them," he continues. "And he is very definite at exactly how that is and is not afraid to hop up on the chair and orate to everyone exactly what he means in case you do not understand. He's a great salesman, he's a great debater, he's a great storyteller, he's becoming a really good storyteller. He and I, we riff up stories and he knows, we give a little wink when we embellish somewhere, like 'Oh, that didn't happen, but hey, it's better for the story,' but for the most part he's very active and he's becoming a good buddy of mine now as he's reaching 12."

McConaughey said he wouldn't mind if his children -- which includes 10-year-old daughter Vida and 7-year-old son Livingston -- end up following him in the entertainment industry.

"Look, I want them to do whatever it is they're fashioned to do," he says. "Whatever they have an innate ability to do, and are willing to put in the work to get better at it. Whatever that is, I want them to do that. If that becomes something in the industry that I'm in? Bravo. I've met some of the most wonderful people in my life in my industry, I love what I do. Everybody on a set of a film or a TV show has to be great at their particular job for it to work."

"I have already started to employ them," he adds. "They do all my photo shoots now. They did the Longbranch ads. Levi did. He's the DP, he's the one going out there, we're setting up the GoPros. We're doing the editing. So, maybe I'll have a little McConaughey production crew here, and we'll be a one-stop shop."

McConaughey said he he's always known he wanted to be a dad since he was eight years old.

"I learned this, the idea of being a father and although that's the only thing I ever wanted to be, I've learned that fatherhood is a verb, it's not just about being half of making the child," he notes. "It's the verb of the work you do after your children are born and there's a great, incredible responsibility and privilege to be in that position. ... What better job could we have? What better legacy could we leave behind than our children? ... And my favorite project I've ever worked on is fatherhood and I'm trying to do my best at it."

The 50-year-old actor acknowledged his candid new memoir -- which includes him opening up about being blackmailed into losing his virginity at 15, and also being molested by a man when he was 18 -- was not for his children to read now.

"This has some real life to it that they need to be older," he explains. "Look, it's like a lot of the films I've done or TV, they're not ready to see Dallas Buyers Club, they're not ready to see True Detective. You know, they've seen very few of my films. It would confuse them in ways they do not need to be confused because they're not old enough to understand the context of that situation in life. I think when it's time for them to read it, I'm very excited about it, that they know me well enough and they'll go, 'wow,' but not judge me any differently -- just see me as more, 'Wow, that's a lot of things that Papa was doing before we were ever even in this world. There's a lot Papa was doing when he went away to work each day, what a full-life Dad led.'"