The "Saturday Night Live" alum is to play Rusty, Mike's brother, while John Cullum is to guest star as the guys' father, Big Mike.
Series regulars Neil Flynn and Patricia Heaton play Mike and Frankie Heck, a middle-class couple with three kids.
"Mike begrudgingly invites his brother, Rusty, who is temporarily living in a tent, and his father, Big Mike, who has recently broken his hip, to join him for the annual Heck family Thanksgiving," the network said in a synopsis Monday. "But when Frankie observes the macho Heck men's non-communicative nature, she encourages a not-so-receptive Mike to engage them in a real conversation and express their feelings."
The episode is to air Nov. 24.