Nicole Scherzinger worries fans with protruding ribcage and ultra slim waist as she leaves The X Factor studio

Showing off a startlingly slim waistline and protruding ribcage, Nicole Scherzinger waved to crowds outside the ITV studios following Sunday night’s X Factor show.

Wearing a black crop top and wide-leg trousers, the 35-year-old appeared to have shed a dress size, and worried fans took to social networking site Twitter to ask if she had ‘gone too far’.

Viewer Amy Robins tweeted: ‘Nicole Scherzinger is ruining herself by becoming so skinny, she looked tiny.’