Looking no further than her go-to milliner Stephen Jones, who crafted her stunning black fascinator, the 36-year-old pulled the look together with a pair of nude heels and a black clutch by the luxury French design house.
The Duchess of Sussex tried out a new colour in her royal wardrobe.
The christening was held at the Chapel Royal at St James' Palace, the same location where Meghan was baptized and confirmed shortly before her May 19 wedding to Harry.
The day after the christening of Prince William and Kate Middleton's third child, Prince Louis, the proud parents, accompanied by Prince Harry and his new wife Meghan Markle, attended the 100th birthday celebrations of the Royal Air Force.
The tribute to the RAF, which became the world's first independent air force when it was founded as a separate entity from the British Army and Royal Navy in 1918, began with a service at Westminster Abbey.
The royal couple made their first official visit to Northern Ireland in March.
This includes attending a Gaelic sports festival at Croke Park and a summer garden party at the British Ambassador's residence.
The royal brothers wore their military uniforms as they arrived at Westminster Abbey Tuesday morning for a service marking the centenary.
Of course, Meghan looked absolutely stunning as she strutted down the airport runway wearing the green Givenchy dress.
Prince Louis' grandparents on both sides, Carole and Michael Middleton and the Duke and Duchess of Cornwall, all beamed with pride as they arrived at St James' Palace.