The 20-year-old glamour model, from Cheshire, has become the favourite following the departure of fellow female housemate Bea on Friday.
However she has appeared frustrated in recent days, hitting out at Kris – who she became close to in the house.
She has suggested that he came on to the show “for all the wrong reasons” and added that she only claimed to have been intimate with him to try to get gossip out of Noirin.
Despite this, bookies Ladbrokes have slashed her odds of winning to 5-2, with Marcus next in the betting at 11-4.
“Sophie has been just off the pace throughout the series,” said Ladbrokes spokesman Nick Weinberg. But she’s made her move at the business end of the show.”
Sophie – who recently reverted back to her real name after changing it to Dogface to win housemate status at the start of the series, is one of only two women left in the house. Lisa is the only other female housemate remaining.