'Life Unexpected' star Kristoffer Polaha is set to romance Sarah Michelle Gellar in CBS's 'Ringer.'

According to TVLine, Polaha will play Gellar's Siobhan's lover. Here's the catch -- he's currently married to Siobhan's best friend! In the pilot, Gellar plays twin sisters, Siobhan and Bridget, both women with quite a few secrets -- and bounties! Bridget poses at Siobhan, thus romantic entanglements begin. Oh, Siobhan is also married.

Get all that?

In other casting news ...

• HBO has added an impressive list of names to its 'Hemingway & Gellhorn' TV movie. Joining Clive Owen and Nicole Kidman are Molly Parker, Parker Posey, David Strathairn, Rodrigo Santoro, Lars Ulrich, Santiago Cabrera, Saverio Guerra, Peter Coyote, Diane Baker and Tony Shalhoub. [Deadline]

• Jordana Spiro has been tapped to star in ABC's 'Lost and Found.' The former 'My Boys' star will play Jo, a New York City-based bartender/party girl whose life is changed when the son she gave up for adoption 18 years ago shows up on her doorstep. [Deadline]

• Thomas Dekker has joined The CW's 'Secret Circle.' Dekker will play Adam, the oldest member of a coven and a potential love interest for Cassie (Britt Robertson). [TVLine]

• Keira Knightley will voice Tinkerbell in Syfy's 'Neverland.' This is Knightley's American TV debut. [Deadline]

• Donal Logue is bouncing back from the 'Terriers' cancellation with 'Hallelujah.' Logue joins Jesse L. Martin and Terry O'Quinn in the Marc Cherry pilot. [Hollywood Reporter]

• 'House' veteran Jennifer Morrison has joined ABC's 'Once Upon a Time.' Morrison will play Anna, a woman who is drawn to a world where fairytales may be real. Josh Dallas, Jamie Dornan and Jared Gilmore also star. [Deadline]

• 'A Mann's World' has added 'Sex and the City' alumnus Mario Cantone to its cast. Cantone will play the salon manager of Don Johnson's Allan's salon. [Deadline]