13 Celebrity Big Brother contestants are isolated from the outside world for 23 days in a custom built house. Watching over these Housemates is Big Brother - heard only via a voice. He is the all-seeing all-knowing authoritarian figure who monitors the Housemates' every move. Every week Housemates nominate each other for Eviction in a secret ballot. The viewers then vote to decide who will be Evicted. The last person left is the winner.