The Irish beauty was shocked when ex-boyfriend Isaac joined the house on Wednesday, just as love appeared to be blooming with fellow-original Siavash.
Freddie, or Halfwit, is 9-4 favourite with Betfair to win the show overall. He holds a Big Brother record for facing the most public votes in a row, five, and surviving the lot. Siavash, the contestant at the centre of the Noirin love saga, is second favourite at 7-2.
Betfair spokesman Michael Robb said: "Our customers clearly think Noirin is finished after all this attention she’s been receiving and make her almost certain to be evicted by the public tonight.
"There doesn’t appear to be any slowing in Halfwit’s march to victory, having been favourite to win from very near the beginning. Punters will surely have taken note of the fact he has faced so many public votes and yet is still there."
BB10 is one of the best series they have done we reckon. We are hooked & cannot wait to see who goes tonight.
You could say that Siavash has learnt his lesson.
After betraying his friend Marcus and cheating on his girlfriend to be with Irish temptress Noirin, he has been tossed aside in favour of a new man.
Noirin was too busy kissing and cuddling Isaac to notice Siavash last night, but he was more than aware of her presence.
Snuggling up: Noirin and Isaac cuddle in bed last night after reigniting their relationship
While Noirin lay in bed with her ex-boyfriend, Siavash sat glumly in the lounge.
Too afraid of what he might see, he sent Halfwit in to check what they were up to.
'The coast is clear,' he then announced. 'I think I shall p*** off to bed.'
As he entered the bedroom Siavash could then be heard whispering: 'Come on - no surprises, no surprises.'
Siavash cheated on his long-term girlfriend, artist Laura Cogon, to be with Noirin, angering his best friend in the house in the process.
Enlarge Siavash who? Noirin embraces Isaac...
But, after just a few days in her favour, he was forgotten when American Isaac moved in.
The introduction of Noirin's ex upset the other housemates, after it ended the budding romance between the Irish beauty and the long-haired Iranian.
And the outspoken bar owner has also ruffled feathers by branding the other housemates 'a********'.
Noirin said to Isaac last night: 'Tell them about the rectum tree. The rectum tree which is growing near our studio.
'There are a******** falling off it.'
Bea was unimpressed, saying: 'I feel like taking a poo in her pillowcase.'
Up against Noirin: Marcus has fallen for the Irish beauty - but one of them will leave the house this evening
Earlier Noirin had been angered after the other housemates backed her former friend, and keen admirer, Marcus, against whom she is facing eviction tonight.
They visited the diary room to plea for the 35-year-old window fitter to be kept in side by the public.
Noirin, with Isaac in tow, stormed to the bedroom to demand an explanation from 24-year-old Bea.
She initially tried to deny the episode but Noirin, 25, was having none of it.
'Don't make us out to be idiots,' she raged. 'It's not of your business you nosy cow.'
Noirin also branded glamour girl Sophie Reade a 'two-faced bitch' for her part in the plea.
'I'm surprised you think anyone would be supportive of you, Noirin,' Bea replied.
As well as winning the hearts of Isaac, Marcus and Siavash, Dubliner Noirin has also been the focus of previous housemates Sree, Angel and Tom.