A few things are guaranteed to happen every year when the ‘X Factor’ final rolls round.
We get to see some family members in ropey homemade t-shirts, urging people to pick up their phones. Nicole Scherzinger trots off to one of her act’s former workplaces and gets stuck in (we still can’t shake the thought of her in a Greggs tabard, to be honest). And some celebrities get roped in for the annual guest duets.
In the past, some of the biggest names in music have been wheeled out to perform with the ‘X Factor’ finalists, although some unlucky hopefuls have been lumped with whichever artists on the Syco roster happen to be free that weekend.
Here are just 12 of the most memorable celebrity duets from the ‘X Factor’ vaults...
What no one had anticipated at the beginning of 2015's 'X Factor' was that the series high point would come from Ghanian hip-hop star Fuse ODG and the comeback kid Craig David.
Still, this performance gave the final a much-needed jolt of energy, and the whole crowd was on their feet for the rendition of 'Re-rewind'.
For all this is our list of 'most memorable' performances, we had completely forgotten that this bizarre collaboration between Same Difference and Jason Donovan had even happened.
Still, it's worth including, if for no other reason than to see how far 'The X Factor' has come over the years.
Proving it helps to have friends in high places, this duet with Kylie Minogue is basically what pushed Leon Jackson - one of the most overlooked winners in 'X Factor' history - to victory, back in series four.
OK, we'll admit it. This performance is most memorable for the moment that Scherzy literally takes the microphone out of Jahméne's hand, when her own fails.
A year later, Nicole took to the stage once again, this time with eventual winner Sam Bailey.
And despite the passing of 12 months, she still clearly hadn't got the memo about letting the hopeful take the spotlight during the duet, rather than the guest performer.
Alright, it wasn't quite an Alexandra-with-Beyoncé-esque breakdown onstage, but Joe's excitement to be singing with George Michael is truly infectious.
"I can't actually believe that I'm going to introduce this man to the stage... the one and only George Michael" doesn't quite have the same ring to it as "ladies and gentlemen... Mr Elton John", though.
Another stand-out moment from Nicole Scherzinger, this time with a working microphone.
Two people genuinely happy to be sharing the stage with each other. A genuinely lovely 'X Factor' moment.
Back when 'X Factor' guest duets were a new thing, Leona Lewis made a great addition to Take That's 'A Million Love Songs', shortly after the group reunited in 2006.
Simon Cowell later admitted that it was Gary Barlow's advice about not squandering Leona's talent that made him realise what a star she could be.
As much as a triumph for Tulisa as it was for Little Mix, this performance gave the former N-Dubz star a chance to prove to her detractors why Simon Cowell gave her the job on the 'X Factor' panel in the first place.
Matt's duet with Rihanna was so memorable the Daily Mail were still chatting about how 'steamy' it was six months later, and it even attracted complaints to Ofcom from viewers.
Everything there is to say about this iconic TV moment has already been said.
But what we will add is this: the other two guest performers that year were Westlife and Boyzone. Westlife. Boyzone. And Beyoncé.
A bad day to be Eoghan Quigg, eh?