Mark Wahlberg, tough guy actor, faces all sorts of challenges in his action-filled films, but now he’s taking on an even bigger one in real life—he’s going for his high school diploma.

After his rocky youth prevented him from completing his education, Wahlberg is now going to finish high school through a web-based program in Massachusetts. The 41-year-old actor told TV host David Letterman, “I quit kind of during the ninth grade.”

He added, “It’s an actual diploma,” rather than a GED. “I’ve got to take up all the courses that I missed…I’m a little nervous.”

Getting back into studying after more than 20 years away from school is a daunting task, but Wahlberg is motivated, hoping to get his diploma in six to eight months.

He told Letterman, “It’s one of those things where I said, ‘You know what? I’m going to make it happen.’”

What inspired Wahlberg to continue his education at this time? Besides being the father of four kids, Wahlberg has been named an ambassador to the Taco Bell Graduate to Go program that simulates college experiences for members of the Boys & Girls Club of America.

Wahlberg explained, “I’m the ambassador to Taco Bell’s graduate to-go program, they asked me to do this and I was like, ‘Dude, I never graduated.’”

He’s fixing that now, and in a few months, Mark Wahlberg will be a proud member of the class of ’13.