Julianna Margulies has signed on to star in the miniseries, The Lost Room for the Sci Fi Channel and Lionsgate.

Margulies joins Peter Krause in the six-hour series; according to The Hollywood Reporter, she'll play Jennifer, a mysterious woman who contacts Detective Joe Miller (Krause) claiming that her brother was killed for a seemingly innocuous motel room key, one that actually has the power to unlock a door into a room full of unimaginable power. After Miller comes into possession of the key and his daughter (Elle Fanning) vanishes into the room, he forms an uneasy alliance with Jennifer; Roger Bart also stars.

The Lost Room is currently in the middle of production in Albuquerque, NM; look for it the premiere in December on the Sci-Fi Channel.