AMERICAN singer Adam Lambert completes a new-look judging panel for The X Factor Australia.

In an overhaul to the reality singing show, Channel 7 has appointed three judges instead of the traditional four.

Lambert, who was the runner-up on the eighth season of American Idol, joins rapper Iggy Azalea and returning judge Guy Sebastian.

"I am very excited to join The X Factor in Australia as a judge and am looking forward to helping people shine their brightest,"  Lambert said in a statement released by Seven. 

"Australia has always been one of my favourite places to tour. The Aussies I've met are so kind and good humoured- so the thought of getting to LIVE in Sydney is very exciting."

Channel 7's Director of Production Brad Lyons said: "Adam is truly a world class artist, performing on some of the biggest stages in the world. He knows first-hand how hard that first break can be.  His experience and passion will be invaluable for our contestants."