Zak Orth, Sonya Walger Zak Orth, Sonya Walger

Lost alum Sonya Walger and Revolution's Zak Orth have landed guest-starring roles on Elementary, has learned exclusively.

Walger will play Angela White, an Assistant U.S. Attorney whose high-profile case is derailed when her defendant is murdered.  A tough-as-nails prosecutor with her eyes on a political career, Angela's ambitions might be dashed when Sherlock (Johnny Lee Miller) and Joan (Lucy Liu) uncover activities she finds difficult to explain.

Elementary taps Smash star as Joan's new boyfriend

Meanwhile, Orth will play Gabe Coleman, a distraught father whose family was torn apart by tragedy.  While Sherlock and Joan suspect Gabe may be connected to a pair of murders, his actual involvement — and motives — turn out to be more complicated than first believed.

Orth and Walger join the growing list of stars heading to Elementary next season, including Gina GershonRaza Jaffrey and newcomer Ophelia Lovibond. Orth and Walger will first appear in Episode 2.

Elementary returns Thursday, Oct. 30 at 10/9c on CBS.

(Full disclosure: is owned by CBS.)