News Kate Middleton and Prince William Made Their First Appearance Since the Royal Baby's Birth William even delivered a joke at his brother's expense. By Isabel Jones Isabel Jones Instagram Twitter Isabel is an Oregon-born and Brooklyn-based writer and editor with a special interest in pop culture. InStyle's editorial guidelines Updated on May 7, 2019 @ 10:00AM Pin Share Tweet Email There’s never a moment of rest for the royal family. Just one day after the world rejoiced over the birth of Meghan Markle and Prince Harry’s son, Aunt Kate and Uncle William are out on royal business in London. BEN STANSALL/Getty Images The Duchess of Cambridge wore an uncharacteristically casual look at the launch of King’s Cup Regatta on Tuesday. Middleton paired a Parisian long-sleeved white shirt with dark stripes with a set of high-waist cropped navy trousers bearing a four-button front, giving a nautical vibe. The mother of three completed the ensemble with a pair of block-heel pumps, a red clutch, and her ever-perfect blowout. Chris Jackson/Getty Images Prince William stood by his wife’s side in a navy suit with a pale blue open-collar shirt beneath. Chris Jackson/Getty Images Kate Middleton and Prince William Reacted to the Birth of Meghan Markle and Prince Harry's Baby Despite rumors of marital discord, the Cambridges appeared happy as can be during the engagement, with several photos capturing Kate’s seemingly hysterical laughter. BEN STANSALL/Getty Images BEN STANSALL/Getty Images William and Kate also spoke about the new addition to the family, with William joking that he's "pleased to welcome my brother to the sleep deprivation society that is parenting!” and Kate "wishing them the best." "These next few weeks is always a bit daunting the first time around," she warned with a smile. Nothing like a royal baby to lighten the mood.