Kate Middleton, Duchess of Cambridge, was out and about all weekend celebrating Prince Philip's 90th birthday in some fabulous clothes. But, not to be ignored, Pippa Middleton also has a unique style of her own.

While Kate wears regal and royal hats and has been known to wear the same outfit in public more than once, Pippa has a laidback yet classic style, perhaps because she's not in the limelight as much as her sister.

Pippa shined in a chic white gown at her sister's wedding to Prince William in April, but Kate looked equally as stunning in her white, lace Alexander McQueen wedding gown--perfect for the young woman who was about to become a duchess and wife to a prince.

While Kate was attending a charity gala in a gorgeous light pink gown, Pippa took in some tennis wearing a white linen dress and a jean jacket.

So it begs the question, which sister has the best style? Or are the too different to compare?

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