Fifth Harmony are likely to bring up the rear because although head judge Simon Cowell has done wonders building up their confidence and, miraculously, even teaching them to harmonise, they haven't really hit it off with the voting public.
The X Factor final will also feature performances from, you guessed it, One Direction and posturing rap-pop guy Pitbull.
Meanwhile, over on The Voice it's also finals time with performances tomorrow night by Juliet Simms from Team Cee Lo, Chris Mann of Team Christina, Team Blake's Jermaine Paul and Tony Lucca of Team Adam, before the results show on Saturday.
Judging by last week's semifinal showdown it was Simms' rip-roaring It's a Man's Man's Man's World that could just make her the favourite to win. Adam Levine told her she was the one to beat while Aguilera said, "I sing for me, and that's where you sing from, too."
But also putting in bold performances were Chris Mann with Ave Maria ("I felt the heavens open up," said Aguilera) and Jermaine Paul with his take on Journey's Open Arms. It's going to be a close one.
The X Factor USA
When: Thursday, 7.30pm and Friday, 7.30pm
Where: TV3
What: And then there were three
The Voice
When: Friday, 8.30pm and Saturday, 7.30pm
Where: TV2
What: The final sing off
Sci-fi pick: Doctor Who Christmas Special
Less than 24 hours after its screening in Britain, Doctor Who fans will get to unwrap an extra Christmas present with the screening of the special festive episode titled The Snowmen. And what a fantastical fairy tale episode it looks to be.
Not only does the good doctor meet his new companion, an unorthodox governess from 1892 named Clara (played with a strong sense of fun by Jenna-Louise Coleman), but he's roped in to try to save Christmas from an icy nightmare - an army of evil snowmen.
There will be oddball creatures aplenty and, though the Doctor is initially reluctant to become involved (he's feeling a little reclusive after the exit of Amelia and Rory), the determined Clara soon has him down from his cloud and ready to fight.
There will be a few nods and winks to other popular TV shows, the return of previous Doctor compatriots Vastra, Jenny and Strax, and guest stars.
When: Boxing Day, 8.30pm
Where: Prime
What: Can the doctor save Christmas?
Variety pick: The Royal Variety Performance 2012
They've gone all out for the Royal Variety Performance this year, celebrating 100 years since the first show. It will be held in the Royal Albert Hall for the first time in its history, with the Queen and the Duke of Edinburgh both there.
Presenting the best in a year of British entertainment, the show also has a bit of a James Bond theme, helping to mark 007's 50th birthday, with host David Walliams arriving by jetpack and Britain's Got Talent winners Ashleigh and Pudsey performing a Bond sequence.
There are also excellent performances from comedian Bill Bailey, the young cast of the West End musical Matilda performing one of Tim Minchin's compositions, many of the old guard including Rod Stewart and Neil Diamond, recently reformed Girls Aloud, Kylie Minogue, Alicia Keys and Robbie Williams, plus classical stars Katherine Jenkins, Placido Domingo and Andrea Bocelli.
When: Christmas Day, 7.30pm
Where: TV One
What: 100 years of British entertainment
Family pick: The Borrowers
Ah, Christmas Eve, a night full of anticipation and often a lot of present wrapping.
Once you've done the shopping you can sit down with the sticky tape and plenty of wrapping paper, and get yourself in a cheery mood with this annual special from cheeky crooner Michael Buble.
The multi-Grammy winning singer gathers friends Rod Stewart, fellow Canadian Carly Rae Jepsen, country star Blake Shelton and Elmo in his hometown of Vancouver for a night of carol singing, interspersed with some light banter in front of a live audience and a montage with Buble dressed up as an ice-hockey player and a shop mannequin.
Jingle Bell Rock, Let it Snow, All I Want for Christmas is You and Winter Wonderland are all on the setlist, along with Buble's original Cold December Night, taken from his 2011 Christmas album and performed with a 32-piece band.
When: Christmas Day, 7.30pm
Where: UKTV
What: Modern adaptation of a favourite children's story
Festive pick: Michael Buble: Home for the Holidays
This is not the first time that Mary Norton's wonderful 1950s children's books have been adapted for the screen. There were the BBC versions in the early 90s, the 1997 film with John Goodman and Jim Broadbent, and the animated Japanese version from Studio Gibli titled Arrietty.
Now the BBC have had another go at it with a 90-minute TV version starring Christopher Eccleston, Stephen Fry, Robert Sheehan, and Sharon Horgan.
The movie brings the moving story into the 21st century, telling the tale of the tiny Clock family who live beneath the floorboards in the Driver family home, undetected until young Clock daughter Arrietty befriends little James Driver.
This leads them to the sewers and a small city of other little people like themselves, but not before Mrs Driver has contacted Professor Mildeye, a man who wishes to study the little people and sets out to capture them.
When: Christmas Eve, 5pm
Where: TV3
What: TV to wrap your presents to
- TimeOut
