The X Factor star will join finalist Eoghan Quigg on the label after Simon Cowell's own company Syco refused the chance to take her on.
Quigg was signed by the firm earlier this month, according to The Sun.
An RCA spokesman told the paper: "I can confirm we have signed Eoghan Quigg. He is a huge talent and everyone is very excited to be working with him."
Cowell's representative said that his label had decided to focus solely on X Factor winner Alexandra Burke.
Runners-up JLS were recently signed to Epic Records.
RCA, Epic and Syco are all part of the Sony Music group.