According to Variety, Chloe Sevigny has joined the cast of the David Fincher thriller Zodiac, co-produced by Warner Bros. and Paramount.

Sevigny will play the girlfriend of Robert Graysmith, a San Francisco Chronicle cartoonist who tried to crack the mystery of the infamous serial slayer. The Zodiac killer terrorized the San Francisco area from 1966-78, committing at least 37 murders and documenting his exploits in snide missives mailed to the newspaper. Jake Gyllenhaal plays Graysmith.

Sevigny's currently starring in the new HBO skein "Big Love" opposite Bill Paxton. She will also appear in two pics unspooling at the upcoming Toronto Film Festival: Thom Fitzgerald's "3 Needles" and Phyllis Nagy's "Mrs. Harris."