Emma Willis presented the spin-off show Big Brother's Bit on the Side, alongside Jamie East and Alice Levine.

Marcus Bentley returned as commentator for the live shows and highlights whilst also providing voice over for viewer competitions.

[3] Following intense press speculation, the exact line-up of celebrity housemates remained a mystery until launch night.

[4] The series was won by Irish traveller and reality television star Paddy Doherty, with Kerry Katona as runner-up.

Former Big Brother winner Brian Dowling replaced Davina McCall as the presenter of the show.

[2] From 23 July 2011, trailers announcing the imminent return of the series were aired on Channel 5 voiced by Marcus Bentley.

It featured a large cast of past housemates dancing and miming in the streets, finally meeting up in a park with CGI effects adding a fly-past with coloured smoke overhead.

[7] With varying controversy, there was no 24-hour live feed in Celebrity Big Brother 2011 unlike most years on Channel 4.

The on-screen graphics and highlights editing were the show's most biggest change to date with names superimposed over the housemates and music used in every scene.

It featured a bar, gym, sauna, an open-plan bathroom, the UK series' largest swimming pool thus far.

[10] The luxurious feel was enhanced by a dramatic entrance way to the diary room with strip lighting and mirrored surfaces.

In a break with the original convention of no contact with the outside world, during visits to the diary room, housemates were invited to answer trivia questions contributed by Facebook members during the spin-off show, Big Brother's Bit on the Side on 5*.

Kerry Katona was announced as the first celebrity housemate to enter the new Big Brother house followed by American Pie actress Tara Reid[11] Reality TV stars Paddy Doherty from My Big Fat Gypsy Wedding and Amy Childs from ITV 2's The Only Way Is Essex joined them.

Michael Hogan of The Telegraph claimed that many of the housemates are "notable only for who [sic] they married or for taking part in other reality shows".

Lauren Harries acted as fashion expert on the launch night show, castigating the styling of the new housemates.

[3] The main elements of the classic Big Brother format have remained in place since the shift to Channel 5.

Amy Childs (born 7 June 1990) is a British reality television star and model, best known for appearing in the ITV2 semi-reality programme The Only Way Is Essex, for the first two series.

[5] Darryn Lyons (born 19 August 1965) is an Australian paparazzo, media personality and entrepreneur, best known for his paparazzi work in Britain.

Lyons gained widespread media attention when he sold a photograph, which was used to support a claim that David Beckham was having an affair with his personal assistant Rebecca Loos.

[5] Jedward (born John & Edward Grimes; 16 October 1991) are an Irish identical twin singing duo, who rose to fame appearing as finalists on the sixth series on The X Factor.

[5] Lucien Laviscount (born 9 June 1992) is a British actor and model, most famous for playing Ben Richardson in the ITV soap opera, Coronation Street and Jonah Kirby in the BBC drama, Waterloo Road.

[5] Patrick "Paddy" Doherty (born 6 February 1959) is an Irish traveller, bare-knuckle fighter and television personality, who featured on Danny Dyer's Deadliest Men and the 2010 Channel 4 programme My Big Fat Gypsy Wedding.

[16] She attracted public criticism when a photograph of her wearing nothing but a bed sheet, and also looking outside to the House of Commons, had appeared in the London Evening Standard newspaper.

[18] Former Harrods owner Mohamed Al-Fayed entered the house as a houseguest on Day 3 and set the celebrity housemates a task based on dressing up as Egyptian mummies.

[19] On the live eviction show of 26 August, Brian Dowling confirmed that the Michelin star-winning celebrity chef and restaurateur Marco Pierre White is visiting the house "to turn up the heat" on Day 10.

[20] On the Day 12 "Fright Night"-themed task, American actors Anton Yelchin and Christopher Mintz-Plasse visited the house to present the winning housemates with tickets for a screening of their film.