Behold, the royal baby bump! Six months into her first pregnancy, Kate Middleton is finally really showing -- and it suits her well. On Sunday, April 21, the expectant Duchess of Cambridge attended the annual National Review of Queen's Scouts at Windsor Castle, where she offered one of the best glimpses yet of her growing belly.

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Stylish as usual in a mint-green Mulberry cotton-tweed coat, a Whiteley Cappuccino pill box hat, and her favorite LK Bennett "Sledge" heels, the 31-year-old first-time mom-to-be looked radiant and healthy. She smiled widely as she mingled with some of the nearly 3,000 guests who had gathered to watch the parade, which honors young Scouts for their outstanding personal achievements.

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The Duchess -- who volunteers with the Scout Association and recently took part in a training day at a Scout camp outside London -- assisted in handing out the Queen's Scouts Awards, the highest possible honors for young Scouts. She also met with Chief Scout Bear Grylls, of the show Man vs. Wild, who became one of the U.K.'s youngest Chief Scouts in 2009 at the age of 34. Grylls said Middleton had been "an incredible role model" within the organization and credited her with showing people that "Scouting's not just for boys."

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"She's also such a generous volunteer and everyone is so excited to have her in the Scouting family," he raved. "Many people have followed her lead and are getting involved and enjoying the adventure."

Prior to the event, Prince William's wife visited Queen Elizabeth, who turned 87 on Sunday. A Buckingham Palace rep tells Us Weekly that Her Majesty is "celebrating privately at Windsor Castle."

This article originally appeared on Kate Middleton Shows Off Growing Baby Bump in Chic Coat at Scouting Event: Picture