Meghan stuns in chic black gown as she joins Harry, Kate and William at military service

The Duke and Duchess of Sussex attended the RAF Centenary alongside the Duke and Duchess of Cambridge at Westminster Abbey today.

A snapshot of the four young Royals was shared to Kensington Palace's official Twitter account, and show Meghan, the Duchess of Sussex holding Prince Harry's arm.

She wore an elegant black A-line Dior dress with matching black Stephen Jones fascinator while the Duchess of Cambridge chose a pale blue McQueen dress with wide collar.

Catherine also pinned the Dacre Brooch - a symbol of her patronage to the air cadets - to her lapel. Read more on our Twitter, @amomama_usa

Both wore cream-colored high heeled shoes, while the Dukes of Cambridge and Sussex donned their military uniforms.

As reported by ET Online, this is Catherine's second public appearance this week as members of the Royal Family gathered at St James's Palace yesterday for Prince Louis' christening.

Queen Elizabeth was absent from the christening service; she attended the RAF centenary service dressed in a lavender blue coat dress with matching hat.

Catherine is still on maternity leave but attended the RAF service because she took over the title of Honorary Air Commandant of the Air Cades from Prince Philip two years ago.

William also has a rich history serving the RAF's Search and Rescue in North Wales, while Prince Harry joined him briefly at RAF Shawbury.

According to People, the Queen and Prince Charles presented a new Queen's Colour to the Royal Air Force, and members were gathered at Buckingham Palace for the event.

The event will included 100 aircraft flying overhead the Palace, while a mass rifle salute will take place on the ground.

After the RAF service, the Duke and Duchess of Sussex will travel to Dublin for a two-day tour of Ireland, at the behest of the Queen.