Kate Walsh and Taye Diggs

Since Private Practice's Addison (Kate Walsh) issued an ultimatum to Sam (Taye Diggs) — have a baby with her, or they break up — she's faced with their relationship ending. Oh, and there's a new admirer for Addison, played by Benjamin Bratt.

Benjamin Bratt joins Private Practice

Still, Walsh insists: "It ain't over until it's over."

The couple's problems are "dealt with in a really fabulous, very adult, real way," she continues. "What I love about the relationship is I think it's a very valid dilemma that a lot of women can identify with. She wants a child and Sam's already got a child and a grandchild. What do you do? Their situations are kind of undeniable, so we'll see how that works out."

A new suitor comes into town with "a very tempting proposition." Though Walsh stayed mum on dishing out additional details on what develops between Addison and the mystery man.

The pressure between Sam and Addison, as well as this new suitor, will build until the final seconds of the finale, which Walsh says has "cliff-hanger elements to it."

Audra McDonald to exit Private Practice

The finale also includes the exit of Naomi and the actress who portrays her, Audra McDonald, who decided to leave the series so she could spend time with her New York-based family. "It makes me very sad, even talking about it now." Walsh says. "I will miss her deeply. There's so much that happens with everyone, including the way Audra exits, that [the finale] feels like it's a movie. The way Naomi leaves is beautiful and romantic and I'm definitely a part of it."

 Private Practice airs Thursdays at 10/9c on ABC.