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The episode, called "Darlene v. David," finds David Healy (Galecki) making an unexpected visit to the Conner family home to see his ex Darlene (Sara Gilbert) and their kids, Harris (Emma Kenney) and Mark (Ames McNamara), after many years away.
The first preview shows throwback footage of the young lovebirds to remind fans their romance was always ... "complicated."
The clip then flashes forward to show a grown-up, bearded David nervously greeting Dan (John Goodman) and Roseanne (Roseanne Barr), who aren't exactly thrilled by the absent dad's surprise appearance.
A second clip shows David hilariously struggling to climb through the window of Darlene's old bedroom like he did as a teen.
"Why are you coming in the window anyway?" Darlene asks her ex.
"Does your dad still live here?" a terrified David answers. "That's why I'm coming in through the window."
According to ABC, "Darlene v. David" finds David unexpectedly showing up for his daughter Harris’ birthday after being absent for years, forcing Darlene "to re-examine their relationship and the rest of the family."
"I'm excited. I'm excited to see it," he said. "I was a big fan of the show before I had anything to do with anyone on the show, and so I'm excited."
"Roseanne" airs Tuesday at 8 p.m. EDT on ABC.