06/14/2012 AT 02:00 PM EDT
is an award-winning actor and producer, and he's about to add a new title to his resume – high school graduate.
Wahlberg, 41, never finished high school when he was growing up in Boston because various run-ins with the law
as a teenager landed him in jail rather than in a classroom.
"I quit kind of during the ninth grade," Wahlberg told David Letterman on The Late Show
Monday. "They're going to give me whatever credits I already have, which is probably like one or two."
But Wahlberg plans to earn his diploma through a new program in Massachusetts that offers high school courses online.
"It's an actual diploma," not a GED, he told Letterman. "I've got to take up all the courses that I missed."
Added the Ted star
: "I'm a little nervous."
Wahlberg said he intends to do much of the coursework during "downtime" on sets and hopes he can finish up within six to eight months.
"It's one of those things where I said, 'You know what?' " he told Letterman. "'I'm going to make it happen.' "