'Stranger Things' season 4 set photos confirm return of 'Papa' Matthew Modine was spotted on the set of "Stranger Things" season 4 in Atlanta, Georgia. January 29, 2021 07:08 GMT Matthew Modine has long since hinted at his return as Dr. Martin Brenner a.k.a Papa in "Stranger Things" season 4, and recently leaked set photos from the set confirmed his appearance. Fan account Stranger Things Spoilers tweeted a couple of photos of the actor behind the wheel of a car. He had a face mask on and a red bandanna on his head. The fan simply captioned the snaps, "he's back." Modine played an important role in the first season of the Netflix series. He was missing in the succeeding seasons although his return was hinted in the third when a former Hawkins Lab employee told Eleven (Millie Bobby Brown) that her Papa is alive.