American socialite Paris Hilton is "concerned" after hearing a svelte blonde woman is impersonating her around the world.

The unnamed Hilton lookalike is in her 20s, carries a teacup Chihuahua like the reality TV star's beloved pet TINKERBELL, and repeatedly uses her catchphrase, "That's hot."

A source tells the New York Daily News, "Once, this woman tried to get VIP treatment at Disneyland. She was telling people she'd call (Disney chief) Michael Eisner.

"Another time, she tried to check into the Four Seasons in Maui, where the Hiltons have stayed before. She was asking for upgrades. The hotel management finally got suspicious and called (Paris' parents) RICK and KATHY, who told her Paris wasn't even in Hawaii.

"The Hiltons got really worried when they heard someone had applied for a credit card in Paris' name. They're starting to wonder if there's more than one person pretending to be their daughter."

Hilton's publicist admitted the star was "concerned" to hear about her doppelganger.