Hopper manages to befriend a prison guard, who looks very familiar (Picture: Courtesy of Netflix)

Warning: spoilers ahead for Stranger Things season 4 volume 1.

The return of Stranger Things on Netflix means far more spookiness from the Upside Down than fans could have anticipated, as new villain Vecna inflicts unimaginable horrors on the town of Hawkins.

Season 4 sees the gang scattered across the country and the world, after Eleven (Millie Bobby Brown) moved to California with the Byers family while the others stayed put.

Jim Hopper (David Harbour) was presumed dead after the explosive season 3 finale, but it turned out that he survived, before being imprisoned by Russian forces.

The former police chief manages to sort of befriend a prison guard, who has a message sent to Joyce Byers (Winona Ryder) informing her that Hopper is still alive.

Some might have found prison guard Dmitri fairly familiar, considering the significant role he played in Game of Thrones.

Who plays the prison guard in Stranger Things season 4?

The prison guard, whose name is Dmitri and who uses the code name ‘Enzo’ when speaking to Joyce, is played by German actor Tom Wlaschiha.

Tom plays a pivotal role in the new season of Stranger Things (Picture: Tristan Fewings/Getty Images)

Tom, 48, was born in Dohna, Dresden, and one of his best-known roles is as Sebastian Berger in action thriller Crossing Lines.

Who did he play in Game of Thrones?

The actor portrayed a fan-favourite character in Game of Thrones, making his debut in the epic fantasy show in season two as Jaqen H’ghar.

Jaqen H’ghar helped Arya became a fearsome assassin (Picture: HBO)

He reprised the role in seasons five and six, having taught Arya Stark (Maisie Williams) the ways of the Faceless Men when she wound up a prisoner in Harrenhal.

When they bid farewell, Jaqen gives Arya a coin and tells her that if she ever meets a man from the land of Braavos, she should show him the coin and say ‘Valar Morghulis’ – which is how she eventually makes her way to Braavos.

He trains Arya further in the ways of the Faceless Men, who she discovers are a band of assassins who disguise themselves using the faces of the dead.

More: Netflix

For his performance in Game of Thrones, Tom received a nomination for outstanding performance by an ensemble in a drama series at the 2016 SAG Awards.

To celebrate the launch of Stranger Things season four volume one, Tom shared a behind-the-scenes photo on Instagram of himself in character as Dmitri, standing outside a church with battered clothing and fake blood on his face.

Stranger Things season 4 volume 1 is available to watch on Netflix, with volume 2 dropping on July 1.

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