Producer Nigel Lythgoe has revealed his shock at claims American Idol unfairly prejudices against black contestants.

TMZ reports that nine former American Idol contestants have sent a letter to the US Equal Employment Opportunity Commission claiming that they were disqualified from the show because of their skin colour.

The group - including Ju'Not Joyner and Thomas Daniels - say that the only people publicly kicked out of the show have been black, claiming that they used unfair investigations into their alleged criminal history.

They add that none of the wannabe singers disqualified from the show based on their arrest history were actually convicted of the crimes they were charged for.

Producer Nigel Lythgoe told TMZ that American Idol is fair to people of all skin colours. He said:

"We treat everybody the same...no matter the race, religion or sex. I think we've always had a fantastic share of talent from contestants both black and white...I don't think I've ever seen racism at the show."