Sewell is best known for his roles in the films "A Knight's Tale" and "The Illusionist," and in the TV miniseries "John Adams."

He will play biophysicist Dr. Jacob Hood, special science adviser to the FBI, in "Eleventh Hour," which is to debut Oct. 9.

"Called in at the 11th hour, his jurisdiction is absolute and Hood is dogged in his pursuit of those who would abuse and misuse scientific discoveries and breakthroughs for their own gain," CBS said in a news release. "Fighting to safeguard the balance between human cost and scientific advancement, Hood solves the most baffling mysteries and saves countless lives in the process. Special Agent Rachel Young is the decorated FBI protection officer assigned to watch Hood's back."

The show from producer Jerry Bruckheimer co-stars Marley Shelton as Young. Shelton's film credits include "Grindhouse," "American Dreamz" and "Never Been Kissed."