The four most important pieces of advice actor Matthew McConaughey gave Longview High School graduates

Matthew McConaughey graduated from Longview High School in 1988, and he graciously returned to his former Texas hometown to offer advice with a commencement speech to the assembled arena crowd of Longview students, families, friends and faculty.

Here are the four most important words of wisdom that the Longview alumnus gave 2019 graduates during his commencement address:

Dressed in a slim-cut blue suit and an open collared shirt, the Academy Award winning actor said: "Tonight, you are graduating. You've made it this far and I want to tell you that the adventure of life is about to get even more fun — even more exciting — harder, happier, everything. It starts now."

Congenially addressing the large group of graduating Longview High School seniors with his back to the audience and facing the graduates, McConaughey continued: "You may not know where you're gonna go. You may not know what you're gonna do. And that's OK."

"I didn't know what the heck I wanted to do when I graduated from here in 1988," he said. "Thirty-one years ago, I was you."

"I sat here on this night ready to go out into the world," McConaughey recalled. "I traveled; I went to college; I got cast in a movie; I found a career ...31 years ago — I was you — a graduating Longview Lobo."

The Oscar winner continued by sharing what he believed was the most important thing for graduates to know if they want to be successful in the future.

"The most important reason, though, for my success, and for your success — the one thing that we all have that should never be for sale," the 1988 LHS graduate said. "The thing that we give the most of and should protect with our life ...is our heart."

McConaughey added: "As you head out into the world, do not negotiate your heart. It's the most important value you have. People will try to get it from you, too... it ain't for sale."

Weaving imagery based on the military location identification term, 'What's your 20?' McConaughey aligns his travel to the ceremony along Interstate 20 with the heart theme and applies it to the city of Longview, the graduates and the school's recent 6A state football championship win.

He implores the students to ask themselves, "What's my 20? and [to] know it's your heart. That 20, my heart, that got me here today. Your heart: that 20, that's what got you here today and that's what's gonna get you wherever you're gonna go."

In ending his speech, McConaughey urged: "Make your 20 your heart from now on. Go Lobos."

The delighted senior class members and the approving crowd offered applause and cheers from their seats in the outdoor football stadium.

Moments later, the Texas actor was presented his original 1988 high school diploma by a school official.

Showing surprise, McConaughey opened the diploma case, showed a sly grin and asked, "Is it really?"

Upon his visible confirmation of the vintage document, McConaughey exclaimed: "Proof!"