After an eight-year separation, Married... With Children costars Katey Sagal and Ed O'Neill are reunited on tonight's "Old Flame" episode of 8 Simple Rules (8 pm/ET on ABC).

According to exec producer John Peaslee, Sagal's Cate dated O'Neill's character, Matt, back in college. "In the show's back story, [Cate and her late husband Paul] broke up one year and she had sort of a wild year where she dated a lot of people," he explains. "[Matt] was one of the guys she went out with that year."

Natch, Matt's an "Al Bundy-esque" guy whom Cate remembers fondly. She e-mails him "purely for nostalgic reasons, not for anything else," Peaslee notes. "What happens is, he gets the e-mail from her, and he's a man who's ready for a midlife crisis. He basically just dumps his wife, buys a Harley and shows up at her door assuming that they're going to pick up where they left off, and that's not what she had in mind at all."

While the episode won't "go into Married... With Children territory," Peaslee says "it wouldn't be any fun unless you were re-creating that relationship — without calling them Peg and Al."

The Bundy portrayers' reunion is fleeting, though. "At one point, we had thought if we could get him for more that would be great," Peaslee concedes, "but he's busy. He was gracious to give us the one [guest shot] and we were happy to do that." Oh, Allll...