Lewis is on course to be the show's first female winner

The London receptionist, 21, will go head to head with student Ray Quinn to win the coveted ITV talent contest.

"It's unbelievable," said Lewis, who is currently favourite to become the show's first female winner with odds of 1-6. Quinn, 18, has odds of 7-2 to win.

"The only person we can compare Leona to is Kelly Clarkson, a true star," said William Hill's Rupert Adams.

"Leona is by far the best X Factor contestant in three years of the show and we wouldn't dream of taking bets on her achieving at least five number ones in 2007."

Student Quinn said he was "stunned" on learning of his place in the final. "Thank you so much to anybody out there who supported me, it's such an honour."

The winner of X Factor is currently 2-9 odds-on favourite for the Christmas number one single slot, following in the footsteps of 2005's Shayne Ward.

Lytton received an emotional send-off from the dance show

Both singers are mentored by pop mogul Simon Cowell.

Meanwhile, in BBC One's celebrity talent contest Strictly Come Dancing, former EastEnders star Louisa Lytton was knocked out of the show.

The 17-year-old actress performed a tense dance-off against singer Emma Bunton after the two celebrities received the lowest number of votes from judges and public combined.

An emotional send-off saw Lytton, and her partner Vincent Simone, receive a standing ovation from the judges and audience.