Mole, minister and part-time Beyonce shack up in Big Brother mad house

Mario, who was born near Venice and is half Italian and half British, will be set secret missions and have to live undetected - despite his "giveaway" costume. If he is discovered by the 13 main housemates he will be ejected from the show.

Gallery: Big Brother Housemates 2010

The 28-year-old from Essex, who was chosen by tombola, entered the house late last night to looks of surprise and suspicion from the other 13.

Before going in he was told his task was impossible, and informed that "with great randomness comes great responsibility...".

The lowdown on each of the Big Brother housemates

Those taking part include a Beyonce lookalike, a squatter who lives on discarded food, and a former soldier who lost both his legs.

The group of 13, chosen from a pool of more than 80 hopefuls, also included a born-again Christian minister and a bisexual Katie Price doppelganger with a 30G bust.

Contestants learned they had been successful live on TV during the launch programme hosted by Davina McCall.

Six men and seven women were chosen to take part in the 11th series of the reality show, which is being dropped by Channel 4 after this summer.

Each is aiming to make their mark and enjoy their few weeks in the spotlight with the hope of riches and fame.

As usual the show will have its twists. Unknown to the intake of wannabes, the winner of the series in 11 weeks' time will then immediately take part in a further two-week series featuring all-stars from previous shows.

This year's contestants include Beyonce imitator Rachael, who took up her career after being mistaken for the singer at a gig.

"I don't sing, I mime. My agent is always telling me to get voice-coaching and singing lessons but I think Beyonce has got such a great voice I will never be able to sing like her," she said.

Squatter Shabby, whose real name is Keeley, is a film-maker who was once in the running to take the role which Lindsay Lohan won in The Parent Trap.

Steve is an ex-serviceman from Leicester, who was injured by a bomb blast in Belfast in which he lost both legs and one eye. The father of eight was encouraged to take part by his second wife: "My wife said 'Go for it'."

Also taking part is David from Pontypool, a former pest controller turned Christian minister who believes in UFOs and believes he has visited the Sun.

Corin from Stockport paid £4,000 for a boob job to take her from a B-cup to a G-cup and is often mistaken for Katie Price.

Other contestants in the show include medical student Yvette and professional dancer Ife, who has backed Cheryl Cole and appeared on The X Factor.