Meghan, Duchess of Sussex joined Prince Harry, Duke of Sussex, Queen Elizabeth, the Duke and Duchess of Cambridge, Prince Charles and Duchess Camilla at the RAF Centenary where they all attended a Royal Air Force Westminster Abbey service.
The head of the Royal Air Force, air chief marshal Sir Stephen Hillier, said that it is a "hugely important day" and the "pinnacle" of the centenary celebrations.
"Meghan is known for wearing her hair in a looser and more relaxed style, but her hair today is much sleeker and more elegant, with a very tight ballerina-style knot in place of her usual messy bun".
The newlyweds greeted the Archbishop of Canterbury, Justin Welby, ahead of the christening service and Meghan, who shot to fame as Rachel Zane in legal drama Suits, was caught on camera giggling as she greeted the man who officiated her wedding in May.
Well, it seems like there is no bad blood here as the brunette beauty stunned in the gorgeous dress, especially with her softly curled tresses down for the event as she met with various prominent figures, such as Irish writer, academic and broadcaster Sinead Burke.
"It's clearly a style that she feels comfortable with, which is so important when you're stepping out in front of the cameras".
Kate wore a pale mint Alexander McQueen design, while Meghan wore navy.
Prince William served a stint in the RAF Search and Rescue service in North Wales, and Prince Harry also briefly took part at RAF Shawbury. The pair were formally welcomed to the Emerald Isle by Ireland's Taoiseach Leo Varadkar, and over the coming days the couple will meet the people of Dublin and will visit organisations which are central to Irish life.
On June 26, Meghan chose a blush pink skirt and top by Miuccia Prada, for the Queen's Young Leaders Awards at Buckingham Palace.