Nicola Roberts dazzled on stage during Girls Aloud's performance in a polka dot dress. This image appears in the gallery:Girls Aloud - Jingle Bell Ball 2012 Best Bits In Pictures 15. Nicola Roberts dazzled on stage during Girls Aloud's performance in a polka dot dress. Picture: PA Photos 23 images See the full gallery: Girls Aloud - Jingle Bell Ball 2012 Best Bits In Pictures