Eileen Dietz (born January 11, 1944) is an American actress who is best known for her appearances in many horror films such as the face of the demon in The Exorcist and for her portrayal of characters on the soap operas Guiding Light and General Hospital.

As a child, Dietz appeared in commercials with her twin sister Marianne DeFossey, and beginning at the age of 12 she started studying acting at the Neighborhood Playhouse.

She was cast in two memorable roles in the film: Pazuzu the demon (better known as the face of death), and the 'possessed Regan' (the Linda Blair character) in some scenes.

[4]: 75 After The Exorcist, Dietz had a highly active career on television during the 1970s, appearing as a guest star on such shows as Planet of the Apes, Korg: 70,000 B.C., Barnaby Jones, and Happy Days among others.

More recent film credits include Naked in the Cold Sun (1997), Hurricane Festival (1997), Bad Guys (2000), Exorcism (2003), The Mojo Cafe (2004), Neighborhood Watch (2005), Constantine (2005), Karla (2006), Creepshow III (2006), Dog Lover's Symphony (2006), and Tracing Cowboys (2008).