Rachel Reilly, winner of Big Brother 13, was unveiled as the "mystery houseguest" competing again this summer on season 27.CBS had been teasing a secret player all week and dropping clues on social media as to who it was.

Popular reality show "Big Brother" premiered this week, featuring two Texas residents who say they are up for the challenge.

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 season 27 is taking place with a brand new house theme called Hotel Mystere, and it will have mystery challenges for the houseguests left and right.

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

The cast of "Big Brother" Season 27 has been revealed — with one "Mystery Player" set to make a surprise entrance.

The new season of the hit reality competition series "Big Brother" includes new elements including the introduction of a mysterious masked visitor with a secret accomplice and an unknown houseguest to be revealed sometime during the season.

I'm a Big Brother fan, and like Tucker from BB26, I also "really like puzzles!" Especially crossword puzzles. So naturally, it's my idea of a good time to put together a crossword puzzle that's solely focused on Big Brother (U.S. edition).