Markle joined her husband-to-be and Britain's other senior royals including Harry's father, Prince Charles, and his elder brother Prince William and his wife Kate at London's Westminster Abbey for the Commonwealth service.
The service, which is the largest annual inter-faith gathering in the United Kingdom, is held every year to celebrate the Queen's lifetime commitment to the Commonwealth as Head of its 53 countries. On Monday, the couple attended services at Westminster Abbey in honor of Commonwealth Day, which is an annual celebration of the Commonwealth countries. Unlike Meghan, the Duchess of Cambridge did not take part in a course until after her wedding to Prince William.
The queen is the head of the Commonwealth, a group of 53 nations around the world that are largely former British territories.
Meghan, sitting next to Harry's uncle Prince Andrew, looked most amused by her fiance's reaction to the unconventional performance as the rest of the Royals carefully studied the order of service.
In her Commonwealth Day message, the Queen, who is head of the Commonwealth, said: "Through exchanging ideas, and seeing life from other perspectives, we grow in understanding and work more collaboratively towards a common future". She paired the tidy topper with a white coat and navy dress by one of her future sister-in-law's favourite designers, Amanda Wakeley, and anchored the look with blue suede Manolo Blahnik pumps.
"There is a very special value in the insights we gain through the Commonwealth connection". According to the style blog Meghan's Mirror, Markle's Amanda Wakeley midi dress and coat are available on Orchard Mille - although her dress is now low in stock. Together with William, Kate, and Harry, Meghan rounds out what the local press has dubbed the "Fab Four".
Liam Payne's girlfriend, former X Factor judge Cheryl Cole, was nowhere to be seen as he performed.