The 42-year-old, whose shocking receding hairline was pictured yesterday, put on a brave face as she hosted a Fashion For Relief do in Mayfair.

Dressed in a long black gown with lace detail, the supermodel smiled as she posed for photographers on the red carpet at Downton Mayfair in London.

This is not the first time Campbell has sparked concern with her thinning hair, with experts saying she is suffering from traction alopecia – hair loss caused by the use of extensions, the Daily Mail reported.

The supermodel, originally from Streatham, South London, has worn straight extensions over her naturally curly hair for a number of years.

Traction alopecia occurs when the extensions pull on the natural hair causing it to break, and usually affects the hairline just above the forehead or the sides, where the hair is weaker.

It can take between three months to a year for hair to grow back in moderate cases.

But if the pulling continues the hair will never grow back and the only option is a hair transplant.

“It is unclear from the pictures if Naomi’s condition is permanent but given the time that has passed since she was first spotted with this condition it is more than likely that the damage she has suffered is permanent,” she added