Sia and Jason Derulo have been confirmed as guest performers on The X Factor 2015 this week.
It's a first for The X Factor UK on both acts although as it happens they both appeared on The Voice UK this past year.
Sia will be performing her latest single Alive from new album This Is Acting on The X Factor's latest results show this Sunday evening.
She'll be joined by Jason Derulo who will be singing his new song Want To Want Me from his latest record, Everything Is 4.
As well as that, Lionel Richie will make a special guest appearance as he mentors the finalists.
Just four acts remain in the competition after last Sunday night's results show saw 4th Impact booted out in the Quarter-Finals.
Those left are Lauren Murray, who was in the bottom two sing off alongside 4th Impact, Louisa Johnson, Reggie N Bollie and Che Chesterman.
Bookies have installed Louisa as the 'unstoppable' odds on favourite to win in this month's final but anything could happen with Reggie n Bollie being backed as surprise contenders to grab this year's top spot.
Who is your favourite on The X Factor? Vote between the final four here!
The X Factor 2015 is back at the weekend from 8PM on Saturday Sunday with the final four again performing twice.
Only three will make it through to the finale at Wembley Arena on December 12 and 13.