Why she matters: Welch infuses her signature cool into a wide range of looks for clients — whether it's a glam Valentino veil for Wilde, 32, or a satin bomber jacket for Bieber, 22. She also plays to the fans, appeasing #Beliebers by putting the Purpose singer in a sharp Saint Laurent white jacket and tuxedo pants instead of his usual casual duds — and captioning the red-carpet photo, "Merry Christmas."
Top look: Nominated for producing short documentary Body Team 12, Wilde, Welch's longtime client, wanted to look elegant "but not too flashy" on the Oscar red carpet. A white Valentino Couture gown with pleats and a Neil Lane pearl choker hit the perfect note: "She felt like it was the kind of dress Katharine Hepburn would have worn," says Welch, who adds that she knew they had a hit when "people were texting me like crazy."
Red-carpet risk: Vinyl star Wilde took a dramatic turn in a caped Valentino gown with a Jennifer Behr netted veil for the HBO series premiere in New York.
Social winner: Unsurprisingly, Bieber's Grammys looks got lots of attention. The pop star (with his 6-year-old brother, Jaxon) posed backstage in a Saint Laurent satin leopard print bomber jacket and garnered more than 2.3 million likes on his Instagram.