The three X Factor finalists have already recorded their winner's singles, which are tipped to be "sure-fire hits".
Fleur East and Ben Haenow have both recorded the One Republic track Something I Need, while Italian hopeful Andrea Faustini has made Whitney Houston's I Didn't Know My Own Strength his own.
A source said of the three winner's songs: "Whoever wins, the song choices are very strong. They are set to be sure-fire hits."
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Unfortunately for Andrea, the 20-year-old faces a new challenge ahead of the X Factor showdown this weekend. His mentor, former Spice Girl Mel B, has been taken ill with a virus and may not be able to take her seat on the judging panel.
Mel B, 39, fell ill after taking Andrea to London's Royal Albert Hall earlier this week where she introduced him on stage at a concert for a cancer charity.
Andrea has been left to fend for himself since, as his mentor won't see the talented singer for fear of passing on the bug and ruining his chances in the show's final.
A show insider said: "Poor Andrea is feeling abandoned. He is already nervous about the ﬁnal. It is such a massive night, who wouldn't be?
"The poor lad is having to fend for himself backstage in the run-up to the biggest night of his life.
"But Mel can’t help it. She is so poorly and may have to miss the ﬁnal altogether."
At a press conference, Andrea was supported by Cheryl Fernandez-Versini and Louis Walsh, who have no acts left.
Simon Cowell sat with his stars Ben, 29, and Fleur, 26.
An X Factor spokesman confirmed that Mel was "quite ill", and added: "There is a chance she won't make it, absolutely."