Counterpart is an American science fiction thriller television series starring J. K. Simmons. It was created by Justin Marks and was first broadcast on the premium cable network Starz. The series ran for 20 episodes across two seasons. It premiered on December 10, 2017, and aired its final episode on February 17, 2019.

Jonathan Kimble Simmons is an American actor. Considered one of the most eminent male character actors of his generation, he has appeared in over 200 film and television roles. He is the recipient of various Supporting Actor accolades for his performance as the music instructor Terence Fletcher in Damien Chazelle's Whiplash (2014), including an Academy Award, a British Academy Film Award, a Screen Actors Guild Award, and a Golden Globe Award.