Mykelti Williamson Mykelti Williamson

Justified alum Mykelti Williamson will guest-star on CBS' upcoming freshman drama Scorpion, has learned exclusively.

Scorpion stars Elyes Gabel as eccentric genius Walter O'Brien, who builds a team of other super-geniuses to help solve the world's most complex problems. Williamson will appear in an October episode as Gen. Ned Walker, a hard-edged, lifelong soldier in command of the military-controlled Montero Nuclear Reactor, which comes under threat. Initially wary of the presence of a rag-tag bunch of outsiders on his military base, Gen. Walker is at odds with Walter & Co. — until he sees them in action, of course.

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Besides his role as Limehouse on Justified

, Williamson is best known for his big-screen roles in Forrest Gump and Con Air. His other TV credits includeBoomtownKidnapped, and the eighth season of 24.Scorpion, which also stars Katharine McPhee and is produced by the team behind Sleepy Hollow, premieres Monday, Sept. 22 at 9/8c on CBS. Check out an exclusive first look at the show's new key art below:

(Full disclosure: is owned by CBS.)