Four actors have joined HBO's upcoming sci-fi series "Westworld" while Miranda Otto has exited the project.

TVLine reports that "Once Upon a Time's" Eion Bailey has joined the series as Logan. Joining him are Jimmi Simpson and Clifton Collins Jr. as William and Lawrence, respectively. Meanwhile, Babett Knudsen has replaced Mirando Otto as Theresa Cullen. Otto recently landed a series-regular role on "Homeland."

Inspired by the 1973 movie of the same name, "Westworld" is about a Western-themed futuristic theme park whose robotic attractions start attacking the guests.

"Westworld" premieres on HBO in 2015.