A trendy Bel Air pet store that boasts Paris Hilton and Britney Spears among its clientele allegedly gets its canines from puppy mills in the Midwest, according to a TMZ report on Tuesday.

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According to the TMZ report, the Humane Society of the United States revealed undercover video footage linking Pets of Bel Air to the puppy mill.

The store, which also includes Denise Richards, Demi Moore and Robin Williams among its customers, charges thousands of dollars for their dogs. The Humane Society alleges that they buy dogs from puppy mills in Kansas, Oklahoma, Arkansas, Iowa and Missouri.

According to the Humane Society, undercover footage shot at one such puppy mill shows cages of dogs locked up and going "cage crazy." Puppy mills sell dogs who spend their entire lives in cages and are continually bred for years with little hope of adoption.

Pets of Bel Air allegedly told Humane Society investigators that they do not buy from puppy mills, and did not respond to the story for comment, TMZ reports.