Rob Morrow has gone from “Numb3rs” to “Billions,” as Variety has learned that he has signed on to guest star in the upcoming Showtime drama that stars Damian Lewis as a possibly corrupt hedge fund king and Paul Giamatti as a U.S. attorney attempting to find out for sure.

Morrow will play Adam DeGiulio, a counselor to the United States Attorney General. A senior advisor, DeGuilio is described as smart, powerful and highly politically aware. Morrow, who will appear in a couple episodes of the series, is represented by Gersh and Untitled.

The series is created by Brian Koppelman, David Levien and Andrew Ross Sorkin. They are exec producing along with Neil Burger, who directed the pilot.

“Our interest was in sort of digging underneath and understanding who the real people are on both sides of this question, if there’s this battle between capitalism and regulation,” Levien explained to journalists at the show’s Television Critics Assoc. panel in Beverly Hills last summer. “One guy represents one thing in a way, and the other guy is trying to police it. But both are driven by individual things in their personalities and their pasts, and our interest was in trying to sort of get past those preconceived notions into something that we feel is more true and interesting.”

“Billions” will premiere at 10 p.m. Jan. 17 on Showtime.

In other casting news …

Although Showtime was mum to comment, TV Line reports that “Big Love” alum Amanda Seyfried is returning to television and will appear in multiple episodes of the cabler’s much-hyped “Twin Peaks” revival.

“Forever” alum Andy Karl has been cast in a recurring role on NBC’s “Law & Order: SVU” as Sgt. Mike Dodds, or as The Hollywood Reporter points out, the son of Peter Gallagher’s Deputy Chief William Dodds.