Big Brother 27,' hosted by Julie Chen Moonves, premieres on Thursday,. See which houseguests are in power as HoH, who is nominated and who has been evicted so far

Big Brother follows a group of people living together in a house outfitted with more than 100 cameras and 100 microphones, recording their every move 24 hours a day. Each week, someone will be voted out of the house, with the last remaining Houseguest receiving the grand prize of $750,000.

"Big Brother" is set to premiere this week. For Season 27 of the hit reality competition series, the official theme will be "Big Brother: A Summer of Mystery," CBS confirmed Wednesday, July 2.

From a The Traitors-esque hotel setting to the revival of last season’s second chance arena, Big Brother: A Summer of Mystery is already shaping up to be their most dramatic season yet. However, no twist has been more heavily teased than Season 27’s mystery houseguest.

Everything you need to know about ‘Big Brother’ season 27, including how to watch, where to stream the live feeds, and the cast.

Sleeper car bunk room: Behind a secret entrance, this train-themed bedroom straight out of a murder mystery novel contains bunkbeds for six Houseguests (the first time the BB house has had bunk beds since season one!) and a sleek Art Deco design.

"That's a world I don't even want to imagine," Chen Moonves responds when asked about a 'Big Brother' future without her