Reality TV phenomenon Big Brother is returning to UK screens, with millions of viewers expected to watch the 12 contestants being revealed.
This year's house is designed to be more "warm and cosy"
The identities of the housemates vying for the £70,000 prize have been kept secret and will not be revealed until they enter the house on Friday evening.
Now in its fourth series, the show has become a favourite among viewers and tabloids, who become fascinated with relations between the contestants.
The 12 will be locked in a purpose-built house at Elstree studios in Hertfordshire and filmed 24 hours a day, with one voted out each week.
More than 10,000 hopefuls applied to be on the show, from which producers picked 2,700 to audition.
As well as the final 12 who will enter the house on Friday, another 12 will be in reserve.
The show is going back to its original format after last summer's split into rich and poor halves of the house was deemed a failure.
Kate Lawler (right) won last year's £70,000 prize
But one added twist will be that housemates will have to bet at least 50% of their food budget on their weekly tasks - up from the previous 10%.
And the house has been redesigned this year to give the contestants a more "warm and cosy" atmosphere.
There will be a bigger lawn and a cedarwood
arbour where the housemates can relax.
Gigi Eligoloff, the show's executive producer, said the idea of this year's programme was to get "back to basics".
"We want to focus much more on the group dynamic this year," she said.
Fans will be able to watch live pictures from inside the house for up to 21.5 hours per day on digital channel E4.
The show will last more than nine weeks, and bookmakers say it is more likely that a man will win.
Last year, more than nine million viewers turned in to see 22-year-old IT worker Kate Lawler win the contest.
Big Brother, first shown in Holland in 1999, has become a worldwide hit, broadcast in 22 countries.