Before Dwayne "The Rock" Johnson became a famous wrestler, actor or father, he was a kid growing up in an ever-changing home. For years, Johnson and his parents moved to a different city each time his father, a professional wrestler in the '80s, got a new gig. Money was tight, and the strains this lifestyle created didn't go unnoticed by the future movie star.

"I knew that my parents were going through some really, really tough times in terms of their marriage," Johnson tells "Oprah's Master Class."

One particularly traumatic moment happened when the family relocated to Nashville, Tenn. from California. Johnson, who was 15, and his father, Rocky, moved before Ata did, and on the day she arrived in Nashville after her cross-country drive, the tension between mother and father boiled over.

"I'll never forget it. It was probably about 1 o'clock in the afternoon. We were at a restaurant, the three of us, and they got into it," Johnson says. "They got into a very big fight. Not physical, but just really loud arguing."

The three left the restaurant, with Johnson's upset parents getting into his father's car, and Johnson getting into the driver's seat of his mother's car.

"I already had my license at that time at 15," Johnson says. "We're driving down I-65 -- I-65 is a major interstate that runs through Tennessee -- and I'm watching them drive in front of me. Their car starts swerving, and I can clearly see that they are arguing. My old man makes a hard right, and he gets on the shoulder, on the gravel road."

With the car stopped, Johnson's mother got out. The look on her face still haunts Johnson today.

"She had a glazed look over her eyes that I had never seen before," he says.

That's when she walked into traffic.

"She walks right into the middle of I-65, and continues to walk down into oncoming traffic," Johnson recalls. "My heart stopped."

Horns were blowing and vehicles were swerving out of the way to avoid hitting Ata. Johnson sprung out of the car and quickly made his way to her.

"I grabbed her and wrestled her over to the side of the road," Johnson says. "I don't remember what I said to her. I remember she didn't say a thing."

Yet, even without words, Johnson had just learned a powerful lesson.

"In that moment, one of the greatest lessons I've ever learned was how precious life is and how in an instant, it can all go away," he says. "[It] changed me."

Though that incident will stay with Johnson forever, Ata has no recollection of it.

"My mother has no idea that it even happened. That's the irony," Johnson says. "That's also the beauty of it. She does not remember anything, thank God. Maybe it's too traumatic to remember."

"Oprah's Master Class" airs Sundays at 8 p.m. ET on OWN.

More from Oprah.com:

Also on HuffPost:

PHOTO GALLERY Dwayne Johnson Best Moments