WATCH: Promo For Tonight's Season Finale Of WILL & GRACE

On the episode "It's A Family Affair"(Season Finale) - Grace's (Debra Messing) father and Will's (Eric McCormack) mother end up making a surprising and upsetting connection. Jack (Sean Hayes) rebounds from his breakup with a new love. Karen (Megan Mullally) must decide between her husband and her lover. Robert Klein, Blythe Danner, Alec Baldwin and Brian Jordan Alvarez guest star.

Watch Will & Grace Thursdays at 8:00pm on NBC. Starring: Debra Messing, Eric McCormack, Megan Mullally, & Sean Hayes.

Watch the trailer here: