Heidi Montag and Spencer Pratt are this series' American stars entering the Channel 5 reality show. The duo - who have the nickname Speidi - found fame on US series The Hills and have been described in their home country as "reality TV villains".
[Heidi and Spencer]
Spencer released a book in 2009 titled How to Be Famous that claimed "sexy girls get all the attention, not good girls" and "never leave the house without full hair and make-up". He is also a born-again Christian.
Heidi had 10 plastic surgery procedures in one day in 2009, including a nose job, fat injections in her cheeks, neck liposuction and buttock implants. Spencer has previously described the couple as "the most famous people in the world".
[Brian Dowling and Rylan Clark]
Joining the duo in the house is 20-year-old Bedford model Lacey Banghard, whose claims to fame include winning Page 3 Idol and appearing in Nuts magazine.
The model, who has the nickname Bangers, claims that she is tired of jokes regarding her name, claiming that she's heard every single one from men chatting her up in clubs.
Claire Richards from Steps is also taking part, becoming the second member of the '90s pop group to take part. Bandmate Ian 'H' Watkins took part when the show was on Channel 4.
The singer has insisted that her battle with her weight won't impact on her time on the show, commenting: "It's not going to rule my life anymore."
Jockey Frankie Dettori, who is currently suspended from racing for failing a surprise drugs test, also entered the reality show, alongside former footballer Neil 'Razor' Ruddock, who was a last minute addition to the lineup after comic Jim Davidson pulled out.
There is a long list of soap stars taking part this year, including former EastEnders actress Gillian Taylforth, who claims she was inspired to take part by notorious 2012 contestant Julie Goodyear.
The other three soap stars are Neighbours legend and father-of-two Ryan Moloney, ex-Corrie and Beaver Falls actor Sam Robertson, who admits to "fancying older women", and party animal and ex-Heartbeat star Tricia Penrose.
X Factor's extravagant 2012 star Rylan Clark is also taking part in the reality series. Rylan can bank on strong support from his close friend Katie Price, who has promised to campaign and support the singer on Twitter.
Completing the lineup is a former girlfriend of Simon Cowell and ex-drugs and drink addict Paula Hamilton. The ex-model describes herself as a "50-year-old with the body of a 20-year-old" and has had her eggs frozen so she can have a family in later life.
Hamilton has also claimed that she is taking a coconut called Boris into the house, to whom she regularly talks.
Celebrity Big Brother continues tomorrow night (January 4) on Channel 5.
[Celebrity Big Brother 2013 contestants - Photo Gallery]