Self-confessed sex maniac Sam, 23, who has had a boob job, encouraged Maxwell, 24, by saying "You'd be good in bed," while they flirted over the washing up.
"Well you've seen me in the shower," he replied.
A late-night game of truth or dare at white witch Mary's birthday party last night saw Sam bend the rules to her advantage.
"Dare!" she said immediately, but when Mary dared her to kiss Maxwell when he returned from the Diary Room, Sam refused. She had her own ideas.
Instead she said, pointing to Geordie boy Anthony in a clear breach of the rules of the game, "I'll kiss you" before the pair had a long kiss.
Ladbrokes also said there was a big chance of sex after 19-year-old sales girl Lesley made her entrance into the house in a tight, PVC nurse's outfit, leaving little to the imagination. She went on to expose her breasts twice including on the first night in a dip in the plunge pool.
The only other time 'Big Brother' came close to a catching a bonk was on last year's show when Michelle and Stuart allegedly had sex in a makeshift den under the kitchen table but viewers could not see any of the action. The pair have since said that they did not have intercourse.
Jade and PJ in 'Big Brother 3' came close after a night in bed together, but the couple also denied anything had gone on under the duvet.
This year, there is nowhere for the housemates to hide with glass walls in the kitchen and living room, and heat-seeking cameras in the bedroom.
'Big Brother' has turned even nastier by making Zimbabwean Makosi become the 13th "unlucky" housemate after she was the first contestant to enter the diary room.
As the first "unlucky" housemate she will automatically face the public vote on Friday, unless she receives the most nominations this week when she will become immune from eviction.
Makosi is trying her hardest to keep her place in the house by turning the housemates against her. She has already lied to the housemates by saying 'Big Brother' would give them alcohol if she washed up the aprons before saying she would not do it.
Anthony tried to persuade her to change her mind.
"Bite the bullet and do it for the rest of the guys, please," he said.
Makosi then immediately broke down into fake tears and left the living room, only to be congratulated by former Tory speech writer Derek on her performance.
"Darling, you're gonna get an Oscar," he said.
The news comes as an average 7m viewers tuned into Friday night's opening episode, despite the good weather. Last year, 7.3m watched the opening show -- the highest ever for a 'Big Brother' entrance.
The housemates
Anthony, 23, is a 70s dancer from Newcastle who admits to liking "false boobs"
Craig, 20, from Norfolk says he is the best hairdresser in the world and set up his own salon at 19.
Derek, 40, from London has written speeches for the likes of Margaret Thatcher and Michael Heseltine while working in the House of Commons. Gay.
Lesley, 19, a sales girl from Huddersfield, describes herself as "sexy, bitchy and loud" with her "big brown Bambi eyes" and her "very busty and curvaceous" figure as her key assets.
Kemal, 19, an award-winning belly dancer from London, describes himself as the ultimate Diva with a passion for sex, chocolate and the Eurovision Song Contest. Gay.
Makosi, 24, a nurse from High Wycombe, admits people finds her arrogant and self-obsessed. The 13th unluckiest housemate.
Mary, 30, a white witch, has been psychic all her life and claims to have been abducted by aliens seven times
Maxwell, 24, thinks he will be the alpha male of the house and describes himself as "a bit of a geezer".
Roberto, 32, made it into the final of the "Most Handsome Man in Italy" competition. He admits to being an excellent package with few faults. Works as a teacher.
Sam, 23, marketing student from Surrey, she's had a boob job but never told her family. She also once stripped naked on a podium on holiday in Tenerife.
Saskia, 23, promotions girl from London, admits to being a bit of a ladette and said she'll be nominated because of "jealousy, jealousy, jealousy".
Science, 22, from Leeds believes he is a massively talented musician destined for success
Vanessa, 19, a student from London describes herself as "spontaneous, spoilt and selfish."
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