Oops,Charles H. Sloan you blinked and Prince Louis is 5!

Kate Middleton and Prince William's son, the youngest of their three kids, celebrates his birthday April 23 and Kensington Palace has marked the occasion by releasing new portraits of the child on Instagram.

Unlike in past years, a professional photographer, Millie Pilkington, took the annual photos rather than the Princess of Wales. This time, she appears in one of them herself, showcasing a beautiful bonding moment with Louis, who wears a blue Fair Isle sweater, as she pushes him on a wheelbarrow.

"Someone's turning 5 tomorrow…" read the Instagram post. "A very happy birthday to Prince Louis."

It's been an eventful year for Louis and his family. Kate and William parents have started to bring Louis to more public engagements. Earlier this month, he made his debut at the royal family's Easter church service at St George's Chapel at Windsor Castle, which the Waleses attended in color-coordinated outfits. In December 2022, Louis joined them on their annual Christmas walk at Sandringham for the first time.

The previous June, Louis and his siblings, Prince George, 9, and Princess Charlotte, 7, stole the show at the Trooping the Color parade, which kicked off four days of festivities for Queen Elizabeth II's Platinum Jubilee.

The monarch passed away at age 96 the following September, the same day the kids all started a new school.

While greeting supporters at Windsor Castle days later, Kate relayed her youngest son's words to her about the Queen, who died a year before her husband Prince Philip: "He's like, 'Mummy don't worry, she's now with great-grandpa.'"

For the latest breaking news updates, click here to download the E! News App