She was only a child when Big Brother was cancelled. But that hasn't stopped Hallie, 18, a youth worker from London from joining the cast of the newly revamped show.The teen has signed up for what has been dubbed the 'ultimate social experiment' as it returns to screens. She's one of sixteen housemates who on Sunday night entere the brand new Big Brother house before a live studio audience as they prepare to compete for a £100,000 cash prize.