It's all part and parcel of the X Factor final: the last remaining contestants team up with celebrity guest singers on a duet - and if the rumours are to be believed, it's shaping up to be quite the show...
According to tabloid reports, Robbie Williams, Rihanna, Will.I.Am and Christina Aguilera have all signed up to appear in the final, in a last ditch attempt to help each contestant win the X Factor crown.
It's not yet been confirmed who will sing with who, but it is thought that Dannii Minogue is desperate for her boy Matt Cardle to team up with diva Christina Aguilera - who is also believed to be performing a song from her new movie, Burlesque.
'A duet between Christina and Matt would be a magical moment – just like when Beyonce dueted with Alexandra Burke during 2008’s final,' an X Factor insider told the paper.
'Matt’s voice is phenomenal and Christina can hit notes no one has dreamed of. They would be a perfect pairing no matter what song they sang.'
It is also widely speculated that Will.I.Am may be joining forces with Cher, after admitting to being a fan of the rapping teen.