Sienna Miller wearing the ready-ripped Balmain dressYou may have thought you'd seen the last of 'shabby chic' but, in the bizarre world of fashion, threadbare is making a return.

But it doesn't mean you can just dig out your old ripped jeans and be done with it. No, this is the designer "homeless" look.

Strange as it may seem, the impoverished look is catching on. According to the Daily Mail, online street style blogger The Sartorialist recently featured a "stylish" homeless man on his blog and he's not the only one drawing inspiration from the streets.

Designer Erin Wasson claims her new label RVCA was inspired by the homeless of Venice Beach, whom she praised for being "entrepreneurial on a budget" with their style.

Of course, it's not so simple for the celebrities. The grunge look just won't cut it in the glamorous world of the famous.

But Sienna Miller seems to have found an answer. Following her Broadway debut last week, the gorgeous Sienna stepped into the chilly New York night wearing a ready-ripped, threadbare-looking Balmain dress.

"Homeless chic" it may be, but with a price tag of £14,200, this particular designer trend might just prove a little hard to swallow.