Nadine may have upset bandmates Cheryl Cole, Sarah Harding, Nicola Roberts and Kimberly Walsh by saying she is the talent of the hugely successful girl group.
Nadine described herself as the "singer" and reportedly told the 'Guardian' newspaper: "I do most of the vocals".
The revelation comes amid fresh speculation that Nadine, who is based in Los Angeles and is dating American footballer Jason Bell, could leave the all-girl group to pursue a solo career in the States.
Band manager Louis Walsh has never made any secret of the fact that he will make Nadine a solo star if the Girls Aloud members go their separate ways.
Nadine also suggested that she would have been a successful singer even without winning the show.
"Oh, I'm sure we'd all just be the same, somewhere, singing," she said.
Meanwhile Cheryl Cole has she has no intentions of going solo. The pint-sized pop star and 'X Factor' judge said: "That's a horrible thing to think. I mean, I'm not comparing us to Destiny's Child, but they all went off and did their own things but then came back to the group."