Kate Middleton
Kate Middleton grins as Camilla Parker Bowles struggles to button Prince Charles' gloves. Pictured: Prince Charles, Camilla and Middleton leave a service to mark the centenary of the Royal Air Force (RAF) at Westminster Abbey in central London on July 10, 2018. Getty Images/Chris J Ratcliffe

Kate Middleton was pictured in hysterics as Camilla Parker Bowles helped Prince Charles with his gloves.

On Tuesday, a day following Prince Louis' baptism, the Duke and Duchess of Cambridge stepped out together for the RAF celebration. Middleton was caught on camera grinning as she watched the Duchess of Cornwall struggle to button Prince Charles' gloves.

Middleton wore an Alexander McQueen coat for the event. She paired it with a hat designed by Sean Barret. Also present in the event were Prince Harry and Meghan Markle. The Duchess of Sussex opted to wear a dress by Dior and a hat by royal milliner Stephen Jones.

The royals would stand on the balcony of the Queen's London residence to view a flypast of up to 100 RAF aircraft, a parade of more than 1,000 personnel, and a feu de joie.

Initially, Middleton wasn't expected to be at the event as she is still on maternity leave. Last week, Emily Nash, a royal correspondent for Hello! announced that Markle and Camilla would join the Queen at the Westminster Abbey service to mark the centenary of the RAF. She stressed that it's the next royal outing and named the royals who would be attending the celebration without mentioning the royal mom of three.

"BIG royal outing: The Queen, Prince Charles, Camilla, William, Harry, Meghan, Andrew, Edward, Sophie and Edward will attend a service at Westminster Abbey to mark the centenary of the Royal Air Force on July 10, ahead of #HarryandMeghan's visit to Dublin," Nash wrote on Twitter.

"This once-in-a-lifetime flypast will provide an iconic centerpiece for the RAF100 celebrations," said Air Chief Marshal, Chief of the Air Staff, Sir Stephen Hillier about the event. "In our centenary year, we are commemorating those that have come before us, celebrating our current personnel and, ultimately, inspiring a new generation to write the next chapters in the RAF's story."

In related news, on Monday, the royals reunited for Prince Louis' baptism. For the first time, the Cambridge's family of five was photographed together. Prince William and Middleton arrived with 4-year-old Prince George and 3-year-old Princess Charlotte. The Duchess of Cambridge was carrying Prince Louis in her arms.