Chen Moonves tells Entertainment Weekly that she was shocked when told who the mystery houseguest was. And she goes on to say the figure will be very polarizing for viewers, leading to what the Chenbot thinks will be "a strong reaction in both directions." (More polarizing than Pandora's Box?)

"Big Brother" is back this summer with Season 27, where the official theme will be "Big Brother: A Summer of Mystery."

Julie Chen shared photos from the Big Brother Season 27 house shortly after the theme was revealed by CBS. The longtime TV host posted two photos to Instagram on July 2 to tease the mystery hotel theme that could play out like a game of Clue.