Big Brother fans are buzzing about the show’s latest twist, and they think they’ve got it uncovered. During the Season 27 premiere on July 10, the mystery 17th houseguest, Big Brother legend Rachel Reilly, was revealed. But that wasn’t the only surprise in store for fans for this season's "Summer of Mystery."

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.

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.

"Big Brother" announced Tuesday the 16 new Houseguests who will move into the "Big Brother" house and, for the first time ever, have the power to vote in a 17th houseguest.

Big Brother host Julie Chen Moonves had some time to kill during the show's season 27 premiere on Thursday, July 10. The action-packed opener kicked off on a shocking note with the introduction of a mysterious new character called "The Mastermind,