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An eight-months-pregnant Duchess of Cambridge Kate Middleton was glowing and sporting a healthy baby bump at her last public appearance Friday before her maternity sequester begins.

The duchess, 31, stood out in a pale, baby-pink coat and hat alongside her husband, Prince William, and brother-in-law , Prince Harry, both dressed in formal military wear.

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For close royal watchers who looked to the duchess's clothing color as a cheeky nod, or slight hint, to the unannounced sex of the couple's baby, her grandmother-in-law, the queen, was dressed in a blue coat and hat, leaving bettors still at odds over whether the royal heir would be a boy or girl when it arrives in mid-July.

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The duchess and the princes joined the rest of Britain's royal family Friday for Trooping the Color, the annual celebration held to mark the queen's official birthday, which was April 21.

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The celebration included more than 1,000 soldiers, horses and musicians participating in the parade for the 87-year-old queen, who just marked her 60 th year on the throne.

The Duke and Duchess of Cambridge and Prince Harry were joined at the event by their father, Prince Charles, and his wife, Camilla, as well as Prince Andrew and his daughters Princesses ­Beatrice and Eugenie, and the Earl and ­Countess of Wessex with their 9-year-old daughter, Lady Louise Mountbatten-Windsor.

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Noticeably absent from the festivities was the queen's husband, Prince Philip, who was hospitalized June 6 for exploratory abdominal surgery and discharged today. The queen's cousin, the Duke of Kent, accompanied her in the royal glass coach in Philip's absence.

Now the attention of royal watchers is back on Duchess Kate and her highly anticipated delivery. The duchess made her last solo public engagement June 13 when she christened the 3,600-passenger Royal Princess cruise line from Princess Cruises.

Now the duchess will be "playing the waiting game," just like any other expectant mom, according to royal experts.

"She's not going to be running around with a bump that size, so I think she'll be putting her feet up, relaxing, spending time with her family and spending time with William," ABC News' royal consultant Victoria Murphy said of the duchess after the cruise ship christening.