Masters of Sex has reached into Masters’ mysterious romantic past and pulled out Broadway vet Kelli O’Hara.

TVLine has learned exclusively that the Tony-winning actress is joining the Showtime drama’s ’70s-set fourth season as a long-lost love of Michael Sheen’s tightly wound sex researcher. O’Hara’s character, Dody — who will be around for multiple episodes — surfaces to clear up a mystery about their abrupt parting many years ago.

This is hardly the first time Masters of Sex has raided The Great Way way for talent; the series counts among its series regulars Tony winner Annaleigh Ashford.

Other Season 4 guest stars include Niecy Nash (Getting On) and David Walton (About a Boy).

Masters of Sex Season 4 debuts Sunday, Sept. 11, at 10/9c.