X Factor final 2015: When is it on? Who are the finalists? Who will win? Who is performing?

Really it's just all about Adele, isn't it?

ITV tweeted this sparkly mash-up picture of The X Factor finalists (ITV)

When is it on?

The first final takes place at 8pm on Saturday 12 December on ITV. One act is evicted at the end of the show.

The second part happens at 8pm on Sunday 13 December, when the remaining two acts will do vocal battle one last time before a winner is crowned.

Who are the finalists?

There’s 19-year-old Che Chesterman, mentored by Nick Grimshaw; 17-year-old Louisa Johnson, mentored by Rita Ora; and fun duo Reggie 'N’ Bollie, mentored by Cheryl Fernandez-Versini.

Who is favourite to win?

Louisa is the runaway favourite at 1/5 on bookmakers William Hill, while Che is the outsider at 14/1. Reggie N Bollie could be the dark horse, with odds of 9/2.

What will they be singing?

Che is singing “In the Air Tonight” by Phil Collins and “Valerie” by Mark Ronson ft. Amy Winehouse.

Louisa is taking on “Fighter” by Christina Aguilera and “I Believe I Can Fly” by R Kelly.

Reggie N Bollie are going for “Jump” by Kriss Kross” and, wait for it, a mash-up of “Spice Up Your Life” by Spice Girls and “Boom Boom Boom” by Outhere Brothers.

Each each act will also perform their song of the series and the winner’s song.

What will the winner’s first single be?

The finalists have all recorded their own takes of the winner’s song, and Simon promises they are all “brilliant”. “While Reggie N Bollie’s is very different to the others, it’s fantastic and will really work,” he said.

It will go head-to-head with the likes of Justin Bieber, the NHS choir, Adele and the Star Wars theme song for the Christmas number one.

What big names are performing?

Former X Factor success stories Ben Haenow and Leona Lewis will duet together on Saturday, as will Little Mix and Fleur East.

Coldplay and One Direction will be gracing The X Factor stage on Sunday. Then, a certain someone called Adele will make every finalist wonder why they bothered.

What about the finalist duets?

The most exciting part happens on Saturday, when big names stars join the finalists for three duets. These are yet to be revealed, but in the past have included the likes of Beyonce, Rihanna and Robbie Williams.

Louisa is expected to duet with her mentor Rita Ora, while Reggie N Bollie are being tipped to team-up with Sean Paul. That leaves Che with a question mark above his head but apparently his act is “huge”. Elton John? Please?

Whether Adele will duet with an act remains unknown, but she said earlier in the year that she could be tempted so long as they weren’t “rubbish”.

See you on Saturday...