S5, E24: In the season finale, Karen (Megan Mullally) confronts her ex-husband's mistress (guest star Minnie Driver, "Good Will Hunting") before she invites Will (Eric McCormack), Grace (Debra Messing) and Jack (Sean Hayes) on her extravagant yacht for a somber ceremony. While Grace goes into a jealous fit when she meets the sexy co-worker (guest star Nicolette Sheridan, "Knots Landing") of her husband Leo (Harry Connick Jr.). Singer Deborah Harry also guest-stars as herself in the episode. Shelley Morrison also stars.