NY- As anyone who has seen her on screen knows, Cate Blanchett has always been slender.

But the 37-year-old actress’s gaunt appearance startled onlookers as she arrived at a benefit gala.

With her collarbones protruding and looking painfully thin, the Lord Of The Rings star was barely recognisable as she walked down the red carpet at the Metropolitan Museum of Art in New York.

The stick-thin look was not helped by the Oscar-winner’s shock of scarlet make-up or her swept-up hair.

An observer said: “Perhaps it was just an unfortunate trick of the light, but her shoulders and chest were all bony while her collarbones looked really prominent.

“More worryingly, her hair, which had been piled up into a bun, looked thin and wispy — often a sign of dramatic weight loss.”

Other slender stars at the event celebrating the work of French designer Paul Poiret, who died in 1944, included Kate Moss, Lindsay Lohan and Renee Zellweger.

Cate walked the red carpet with a handsome fellow guest

But the observer said: “Although Cate was apparently in good spirits, she was definitely one of the skinniest celebrities there.”

The actress, once a size 12, is said to be a fan of celebrity diet guru Dr Nishi Joshu.

Miss Blanchett rarely speaks about her diet and lifestyle, but she was relatively quick to lose her pregnancy weight after giving birth to her sons Dashiell John, five, and three-year-old Roman.