You can't go wrong with mom jeans and a menswear-look blazer – and that was just as true in 1988 when Diana dressed down for a low-key outing with Prince William. Photo: Tim Graham/Getty Images
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While on holiday in Mallorca, Spain, the princess was trendy in a sunny yellow jumpsuit paired with a metallic belt. Photo: Georges DeKeerle/Getty Images
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The Princess of Wales, wearing a designer and silhouette that her daughter-in-law the Duchess of Cambridge loves today: a strongly tailored skirt suit by Catherine Walker. Diana wore this look during a visit to Indonesia in 1989. Another Kate favorite that is seen here: the ever-present clutch bag. Photo: Jayne Fincher/Getty Images
