Kate Middleton is a fan of Princess Diana's fashion, and she once again made it obvious in a recent photoshoot.

Clarence House shares Prince Charles' official birthday photo today to mark the Prince of Wales' natal day. In the picture, he posed alongside the closest members of the royal family including Prince William, Kate Middleton, Prince Harry, Meghan Markle, and his wife, Camilla Parker Bowles. Prince George, Princess Charlotte and Prince Louis were all present, too.

In the snap, the Duchess of Cambridge can be seen wearing a polka-dot dress that is very similar to Princess Diana's. Rebecka Perring, a journalist for Express, shares a snap of Middleton alongside the late Princess of Wales in their similar outfits.

The People's Princess wore the navy dress with the same print in 1985 at home. In the photo, Princess Diana is holding a pen and seems to be reading something. She was with her lady in waiting and private secretary, Anne Beckwith-Smith.

This isn't the first time Middleton dressed similarly to her late mother-in-law. Back in August, she was seen wearing a gray coat and black hat with a pearl of drop earrings while she accompanied Queen Elizabeth II to church. They were seated in the monarch's vehicle.

Middleton's coat at that time was reminiscent of Princess Diana. Prince William and Prince Harry's mom was photographed walking in Balmoral with Prince Charles wearing a similar gray coat.

The photographed was captured in 1981 when Prince Charles and Princess Diana were celebrating their honeymoon. They were walking along the River Dee.

Aside from following Princess Diana's wardrobe, Middleton take cues from the late Princess of Wales during Remembrance Day. Every year, the Duchess of Cambridge showed up a black outfit with pearl earrings. Princess Diana use the same accessory for the same event when she was still alive.

Last year, Middleton wore the Oscar de la Ranta Pearl Sun Star button earrings. In the previous year, she opted for another pair of pearl earrings. This prompted some royal fans to believe that Middleton is doing this as a tribute to Princess Diana on Remembrance Day.

When Middleton attended an evening event over the weekend with Prince William, Prince Harry, Meghan Markle and Queen Elizabeth II, she donned a Roland Mouret dress with asymmetrical neckline belled sleeves and fluted skirt. She paired it with pumps and a clutch by Jimmy Choo. The duchess didn't forget to accessorize with a pair of pearl and diamond earrings from the Queen's collection, Harper's Bazaar reported.

Kate Middleton and Camilla Parker Bowles
Kate Middleton channels Princess Diana in Prince Charles' official birthday photos with Camilla Parker Bowles. Pictured: Camilla and Middleton smile during the Remembrance Day Ceremony at the Cenotaph on Nov. 13, 2011 in London. Getty Images/Chris Jackson