The recently released "Stranger Things" Season 4 teaser trailer reveals that Tom Wlaschiha plays one of the Russian soldiers in the Netflix series.

The teaser finally confirmed fans' long-held theory that Jim Hopper (David Harbour) is the American captive teased in the Season 3 end-credits scene. Before the preview ends, viewers get a glimpse of the detective with his clean-shaven look. Gone are the beard and long hair. It is unclear how long Hopper has been held captive by the Russians since the climactic Season 3 ending. But if his new look is any indication, then perhaps he has been there for quite some time.

Outside of Hopper's return, viewers caught a glimpse of another interesting character in the "Stranger Things" Season 4 teaser. Wlaschiha, who fans may remember from "Game of Thrones," appears in the early part of the 50-second trailer (at the 0:27 mark) as one of the Russian guards.

Not much is known about Wlaschiha's role in "Stranger Things" Season 4. His appearance suggests he plays one of the correctional officers at the Kamchatka prison camp, according to The Digital Weekly.

The actor is no stranger to playing duplicitous and ruthless characters on TV screens. Wlaschiha played Jaqen H'ghar, one of the Faceless Men, in "Game of Thrones." He also portrayed the mercenary Max Schenkel in the second season of "Jack Ryan." Perhaps he plays an important character in the "Stranger Things" Season 4 story line and not just a cameo appearance.

Fans of the actor also expressed their excitement to see the talented German star as part of the stellar cast of "Stranger Things."

"Iiiiiiiiiiiiiiiii!!!!! I can't express into words how excited I am to see Tom iiiiiiiiiiiiiii@tomwlaschiha #StrangerThings4," one fan commented. Another wrote, "Hopper's alive! But more interesting is #TomWlaschihais in S4 too!! Yass, we missed you."

Is that Tom Wlaschiha? Niceeee! pic.twitter.com/gEIyVxoCHW

— Justin B (@jfb880) February 15, 2020

The writers for the Netflix series also welcomed Wlaschiha to the show in a tweet.

super excited to have Tom Wlaschiha in our Stranger Things family! pic.twitter.com/CjXMGWeA1e

— stranger writers (@strangerwriters) February 14, 2020

The release of the teaser trailer for "Stranger Things" Season 4 confirmed reports that filming for the series started in Russia to tie up the Kamchatka story teased in the Season 3 end-credits scene. Production will reportedly then continue in Atlanta, Georgia and is expected to end sometime in August. Netflix has yet to announce the premiere date of Season 4.

Tom Wlaschiha at the 2013 Monte-Carlo Television Festival. Frantogian/Wikimedia Commons