[Update: The series is one of the best new shows airing today. A must-see if you like cerebral spy thrillers with a low-key sci-fi twist and filled with top-notch acting). COUNTERPART Trailer Reveals Two J.K. Simmons in Starz's New Spy Thriller What if there was another you? A UN employee discovers the agency he works for is hiding a gateway to a parallel dimension. Counterpart, a new Starz original series starring J.K. Simmons, premieres January 21.