Ricky and Kathy Hilton have long had to worry about their wild daughter Paris due to her wild-child party lifestyle, and recent brush with the law.

But it looks as if they might need to turn their attentions to their younger daughter Nicky, 24, who appears to be modelling herself on Amy Winehouse judging from her dramatic weightloss which has left her looking bony and worryingly thin.

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Thinner: Nicky Hilton, seen here in Los Angeles on Thursday, appears to have loss a dramatic amount of weight, leaving her already slim body and her long legs look extremely bony

Bony: A slender Nicky chose a casual outfit to go shopping in

And while wearing a pair of denim shorts, the fashion designer exhibited a pair of ultra-thin, bony legs that would easily earn her a catwalk ban in Madrid.

Her knobbly knees appeared to extend up to her thigh bone, with barely any muscle or fat to fill out her absent curves. A marked contrast from a similar picture of her taken just seven months ago, when an already slim Nicky appeared healthy and curvy.

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Spot the difference: Nicky has lost all her body fat, and some muscle it seems, and looks dramatically thinner compared to the picture of the younger Hilton sister on the right, which was taken in July 2007

Hilton hieresses: Paris and Nicky on a night out

The Hilton's 5ft 7in daughter has up until now managed to avoid the intense media glare afforded her more famous sibling.

But judging by these pictures, if she continues to get thinner, that may not last.

Meanwhile, sibling Paris was seen out with some new reading material. Namely, a copy of celebrity magazine People with friend Nicole Richie on the cover.

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Sister act: Nicky's older sister Paris seen leaving the Four Seasons hotel in Beverly Hills, California. And she's carrying a bag with a copy of People magazine with pal Nicole Richie on the cover

Paris catches up on all the gossip and photos of pal Nicole Richie's new baby Harlow in the new issue of celebrity magazine People

Clearly Paris was eager to get all the news and gossip on pal Nicole's new baby as soon as it hit newsstands.

But the Hilton family's brushes with the law continue as Barron Hilton, the younger brother of Paris and Nicky Hilton, was arrested on February 12 for driving under the influence.

The 18-year-old was arrested on suspicion of driving under the influence after his blood alcohol was found to be nearly twice the legal limit.