CBS' iconic hit summer reality show, Big Brother, is returning for its 27th season on July 10, and its milestone 25th year on air. Little by little, the producers have been dropping hints and tidbits on what to expect, and the first clue was a set of old-school master keys set behind host Julie Chen-Moonves. This first promo sent fans into a fury of predictions and theories. Soon after, producers for the show suggested that this season would be the "most unexpected yet".
Now, though, CBS has released a full press announcement and let viewers in on some of the specifics for the upcoming milestone season. The theme, "A Summer of Mystery", promises plenty of surprises and its share of shocking secrets to be revealed. The house, meanwhile, named Hotel Mystere, is full of wild designs, hidden meanings, and its own mysteries, where not everything is as it seems. There is a whole lot to unpack, so let's break it all down.
Big Brother 27 bringing in a shocking mystery houseguest
While a ton of information was dropped regarding Big Brother 27, perhaps the twist that grabbed most of the initial headlines was the tidbit that there is a mystery houseguest joining the game. While we do not know many details about this specific element, Julie Chen did let us know that the player is a polarizing figure.
While fans have certainly made some speculations, we do not know exactly who this cast member will be. It seems most likely that it will be a controversial former player or potentially a villain type from another CBS show, but neither of those things has been confirmed. It could even be a celebrity or someone who has been in the news or public eye for some recent reason. Given the older aesthetic and key hints, fans believe that the clues indicate a returnee, but as of now, it is purely speculation.
Besides the mystery house guest, the press release also indicated that there will be a masked visitor and a secret accomplice, both of whom could potentially cause some major shakeups in the game. As with the mystery houseguest, fans will have to wait and see how it all plays out.

Big Brother is bringing more than just a mystery guest
The mystery houseguest is certainly the most eye-popping piece of news, but it is far from the only thing that CBS let fans know about. We got a ton of house tour images, and the theme absolutely stands out. USA Today describes it as a "enigmatic yet luxurious version of the Big Brother house defined by hidden passageways, a wineless wine cellar, a vintage aesthetic, a poison bar, and a suspense-filled atmosphere."
According to Julie Chen via USA TODAY, "Things that you think might just be there for decoration actually has a purpose beyond. Our motto is expect the unexpected, and this season we take that motto into the physical being of the house itself."
There is also a return to the bunk beds that originated from season one, which is another possible indication of some old-school returns.
Hotel Mystere is meant to portray a mystery-filled hotel. The reception area is highlighted by 75 key boxes, with clues and secrets to be discovered. The living room is complete with a balcony of chess piece guardians, while the two bedrooms are called the attic bedroom of oddities filled with spooky and haunted artifacts, and the sleeper car bunk room meant to simulate the Orient Express.
A rooftop garden-styled kitchen with string lights, a secretive wine cellar built for whispers, a Victorian conservatory lounge filled with beautiful plants, a venom lounge and poison bar where snakes are the focal point, and a boxing ring gym round out the full set-up. There is a lot to soak in about the over-the-top theming, and of course, there are likely plenty of mysteries hidden within the walls as well.
Big Brother 27 will premiere on Thursday, July 10 at 8/7c on CBS or Paramount+ with a 90-minute episode, and again a second extended 90-minute episode that Sunday. The live feeds will also be accessible on Paramount+ and Pluto TV.
As is typical, there will be three episodes per week, on Wednesday, Thursday, and Sunday, for now, all at 8/7c. For the first time, there will also be special "Big Brother: Unlocked" analysis shows featuring previous players, which will air every other Friday, starting July 25 at 8/7c.
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