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 Season 27 premieres July 10 with 17 houseguests entering Hotel Mystère. Get cast details, house tour, and shocking mystery player reveal.

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.

Before the season 27 premiere, many fans speculated that the mystery houseguest could be anyone from Celebrity Big Brother UK star JoJo Siwa to a Big Brother newcomer like Tom Sandoval from Vanderpump Rules. Viewers even hypothesized that this season, the host herself, Julie Chen Moonves, would join the cast as a contestant.

It's also worth noting that when CinemaBlend spoke to Rachel back in 2021, she was eager to play Big Brother again. Fans may remember she wanted to be a part of Season 22's second All-Stars season, but was not able to play because she was pregnant at the time. Now, it would appear she's playing the game again, but for how long is anyone's guess.

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.

The premiere of Big Brother Season 27 is just days away, but that's not soon enough for some. The house and theme were revealed, as well as the existence of a mystery 17th Houseguest. CBS decided to tease fans just a bit more by dropping a five-second promo featuring five of the new contestants.