Montecito, California - Four years ago, Meghan Markle and Prince Harry welcomed their second child into the world!

To mark her daughter Lilibet's big day on Wednesday, the Duchess of Sussex shared a few never-before-seen photos with the birthday girl.

"Happy birthday to our beautiful girl! Four years ago today she came into our lives – and each day is brighter and better because of it," Meghan wrote.

"Thanks to all of those sending love and celebrating her special day."

The post featured two black-and-white photos – the first a recent snap of Meghan with Lilibet on a boat, and the second a photo of the mom-of-two holding her then-newborn daughter.

Later in the day, the Suits star dropped more personal photos, this time featuring Lilibet and her proud papa.

"The sweetest bond to watch unfold," Meghan wrote under two snaps of Harry and their daughter. "Daddy's little girl and favorite adventurer."

The couple famously named their daughter after the late Queen Elizabeth II, who was often called by the nickname. The four-year-old's middle name also honors a member of the royal family – Harry's mother, Princess Diana, who died in 1997.

A representative for the Sussexes recently told People that Harry ran the first name by his family before making the decision, with his grandmother being the first phone call.

"Had she not been supportive, they would not have used the name," the spokesperson said.

Along with Lilibet, Meghan and Harry also share a son named Archie Harrison, who turned six last month.