Air steward turned TV presenter Brian Dowling is the bookies' favourite to take the Ultimate Big Brother crown as Channel 4 waves goodbye to the long-running reality show.
Dowling, who entered the house in 2001 as an unknown, is expected to beat off competition from other former contestants to be named the viewers' favourite.
The final will also mark the end of Big Brother's 10 years with Channel 4 which announced last summer it would not be renewing its deal with programme-maker Endemol.
The reality show may not end, however, as media tycoon Richard Desmond said he was thinking of reviving it when he took over the Five TV network in July.
This summer's winning housemate, Josie Gibson, 25, from Bristol, was given the opportunity to compete to be named ultimate housemate following her victory last month but quit just two days later, saying she could not handle the sudden influx of new people and missed her old housemates.
Bookies Paddy Power and William Hill both made Dowling the favourite to win, with odds of 2/9.
Chantelle Houghton, who won Celebrity Big Brother in 2006 despite being the only housemate who was not actually famous, is second favourite to win.
The model married Ordinary Boys singer Samuel Preston after the pair met on the show. They split within 10 months and later divorced but viewers hoped for a reconciliation after both returned to the house this summer. Paddy Power offered odds of 7/2 on Houghton winning tonight while Preston is trailing on 33/1.
Third favourite is tantrum queen Nikki Grahame who first entered the house in 2006 dressed as a Playboy bunny. William Hill has Grahame on 10/1 while Paddy Power rates her chances as slightly better on 8/1.
Also in the running for the crown are "Nasty" Nick Bateman who was asked to leave the first series in 2000 for trying to manipulate fellow housemates' eviction votes, Celebrity Big Brother 2009 winner Ulrika Jonsson and Victor Ebuwa, who is best known for a huge argument with fellow housemate Emma Greenwood during Big Brother 5.