Celebrity Big Brother was a reality television series in the United Kingdom which began in 2001. It was a Celebrity version of the "Big Brother" franchise. Contestants must complete challenges while living in a house full of cameras. In some series the house is in London; in some series it is in Hertfordshire. From 2001-2010, it was shown on Channel 4 and was presented by Davina McCall; from 2011-2018, it was shown on Channel 5 and was presented by Emma Willis.