The Prince appeared to catch Meghan's eye moments later, who began to giggle.
After the service, Harry and Meghan met about 100 children in Dean's Yard, behind the historic Abbey.
The Commonwealth Day is an annual, inter-faith event at Westminster Abbey where all 53 nations participate.
The Queen in her address praised the "Commonwealth connection" and said diversity is "a cause for celebration".
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They played Sun Life Stadium, which is now known as Hard Rock Stadium , which is where they will be August 31. Jay-Z and Beyonce will bring their OTR II Tour to MetLife Stadium in East Rutherford, Aug. 2 .
Lifetime have been kind enough to supply us with stills from the movie; one features Prince William and Kate Middleton alongside Prince Harry and Meghan Markle, and the second features an intimate close-up of the couple.
Meghan was dashing in a navy mid-length dress with an Amanda Wakeley white coat, a Stephen Jones beret and navy blue clutch.
Her appearance marks yet another milestone towards joining the British monarch family.
Prince Harry's American fiancée Meghan Markle on Monday took part in her first official royal engagement with Britain's Queen Elizabeth since the couple announced they were getting married previous year.
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He was named to four Pro Bowls while receiving an awesome three First-Team All-Pro nods during those five initial seasons. If Suh is designated as a post-June 1 cut, the team would save $17 million against the 2018 salary cap.
After the Queen greeted performers with a beaming smile and left, the Duchess of Cambridge and Markle bent down to accept posies from schoolgirls, before joining their partners to speak to waiting pupils.
Ms Markle described the service as "beautiful, especially the choir and the music, ' according to a visiting teacher, adding that it was 'great to see people from all over the world so well represented at the service".
"She was delighted and said she was "very, very excited".
Pourquoi Instagram et Snapchat ont retiré les GIFs de leurs stories
Si Giphy prend " l'entière responsabilité de ces événements ", ce n'est pas la première fois que Snapchat propose un contenu raciste.