Jim Wahlberg

A&E's Wahlburgers has already made a star out of Mark and Donnie Wahlberg's' older brother: Wahlburgers' head chef Paul. Now it's time for viewers to meet another member of the clan: their brother Jim Wahlberg.

The middle child of the famous Boston family, Jim steals the spotlight on the Wahlburgers' upcoming summer special (Sunday, 10/9c) as he gears up to run the Boston Marathon. "The marathon this year is about overcoming tremendous adversity and, to me, Jim is the greatest symbol of that," Donnie tells the camera in this exclusive video. "He's bringing a lot of honor to the Wahlberg name by running that marathon."

Odd couples: Real-life celebrity roommates

Check out the exclusive clip below to see why Jim decided to run the marathon and what his notoriously outspoken family has to say about his experience as a runner (or lack thereof):

Wahlburgers' summer special airs Sunday at 10/9c on A&E.