A US lawsuit claims Sony Music Entertainment cheated American Idol contestants including Kelly Clarkson, above, and Carrie Underwood out of at least $10 million (£6 million) in royalties.

The lawsuit was filed in New York by 19 Recordings, a music company founded by Idol creator Simon Fuller.

It says 19 discovered the royalty issue from two separate audits of Sony's records.

Other artists named in the suit include Clay Aiken and Jordin Sparks.