Adam Lambert has stepped from behind the judges' desk on The X Factor AU to perform on the live show.

Adam took to the stage to perform 'Evil in the Night', a track from his 2015 album The Original High.

The performance comes after he took to Twitter last week to show support for The X Factor UK contestant Saara Aalto.

Saara responded to a fan question revealing that Adam is her celebrity crush, to which Adam responded he is sending his love from Sydney and The X Factor AU. Saara then replied that Adam is "one of the artists I respect the most."

Adam continues to judge The X Factor AU alongside Australian music stars Iggy Azalea and Guy Sebastian and former Spice Girl, Mel B. He is also currently in the studio recording new music.

Watch his performance of 'Evil in the Night' below: