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• The first official cast photo from Stranger Things season two reveals one fan favourite is back
• Stranger Things: The new kids on the block and what we know about season 2
On Twitter Reiser shared his excitement, writing that he is "very psyched" over joining the Stranger Things cast.
Actress Berthelsen has been cast as Roman. According to Netflix, she's "an emotionally damaged, magnetic young woman who suffered a great loss as a child. Although she does not live in Hawkins, she is mysteriously connected to the supernatural events at the lab..."
The tone Stranger Things has been compared to several hit movies from the 70s and 80s, including The Goonies, Alien, E.T. and Stand By Me.
Last week a photo was posted to Facebook and Twitter which shows Millie Bobby Brown - who played Eleven in the first season - at the centre of a cast table read, confirming her return to the celebrated show.
Two other new characters were also confirmed, Sadie Sink as Max and Dacre Montgomery as Billy.
Stranger Things second season will debut on Netflix in 2017.