Mark Wahlberg studied for his high school degree between takes on the set of "Two Guns." Christopher Polk/Getty Mark Wahlberg is the executive producer of HBO hits such as "Boardwalk Empire" and "Entourage," he's acted in hit films "Ted" and "The Fighter," been nominated for two Academy Awards, and is worth over a reported $200 million.

But he never even graduated high school — until now.

A year ago, 42-year-old Wahlberg decided to get his degree.

He took online classes and hired a tutor who helped him study between takes on the set of "Two Guns" — but kept it a secret from his co-star, Denzel Washington.

"Denzel was always asking me what I was doing but I didn't want to share that information with him," Wahlberg tells People.com. "Nobody knew, because I felt like I don't like to count my chickens before they hatch, so I didn't want to say that I was doing it until I actually finished it. What if I said I'm doing this and I didn't finish it?"

Ultimately, Wahlberg did earn his degree.

He says a big part of the reason he went back to school was for his four children.

"I didn't want the kids saying, 'You didn't do it, so why do I need it?' They are all wanting to do things in their future that require an education," Wahlberg told People while presenting scholarships to select Taco Bell employees in Irvine, Calif., as part of its pilot program.

Now that it's over, the actor says "It's also a huge sense of relief. I wondered, 'Why didn't I do it when I was there?' It's so much harder at 41 going back and trying to do all these difficult tasks."

Wahlberg, who had a troubled childhood, dropped out in ninth grade after he was charged with attempted murder.

"My circumstances were not unlike millions of other teens today, who live in tough working class neighborhoods surrounded by drugs, violence and crime, and who struggle to stay on the right path without positive influences," Wahlberg wrote in a revealing item on The Huffington Post.