The Duchess of Sussex shared two snaps of Princess Lilibet with Prince Harry, as she dubbed her daughter, "Daddy's little girl".
The previously unseen photographs show a newborn Lilibet gazing up at her father, while swaddled in a geometric blanket.
A besotted Harry gently holds his daughter in his arms in front of a wall with a tree mural depicted on it.
A second more recent image shows the father and daughter duo taking a stroll together along a palm tree-lined beach.
The pair are barefoot and holding hands, with Lilibet sporting a pink tulle dress and a raffia visor hat.
"The sweetest bond to watch unfold. Daddy’s little girl and favorite adventurer. Happy birthday Lili!," Meghan captioned the shots on Instagram.
It comes just hours after the Duchess posted intimate family photos of Lilibet to mark her fourth birthday.
Meghan shared a black-and-white snap of herself cuddling Lili, who was sat on her lap, with the pair both sporting windswept hair, seemingly on a boat.
The second image showed Meghan tenderly cradling newborn Lili as she enjoyed skin-to-skin time with the new addition to her family in 2021.
Meghan wrote: "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.
"Thanks to all of those sending love and celebrating her special day!"
Harry and Meghan are typically protective over Lilibet and their son Archie's privacy, usually only releasing photos of the youngsters from behind, but in the more recent photo, Lili's eyes and the top half of her face could be seen, with her nose and mouth and the rest of her face covered by Meghan's arms as she hugged the Princess.
Growing up in the US
Lilibet Diana Mountbatten-Windsor was born on 4 June 2021 at Santa Barbara Cottage Hospital.
Her names are a nod to the late Queen Elizabeth II's childhood nickname and Harry's late mother, Diana, Princess of Wales.
She only became entitled to be a Princess when her grandfather the King acceded to the throne, because of rules set out by King George V in 1917.
Harry and Meghan started using their children's royal titles after Lilibet's christening in 2023, following correspondence with Charles about the matter.
Lilibet is thought to have only visited the UK once in her lifetime, in June 2022, which coincided with the tot's first birthday and Queen Elizabeth II's Platinum Jubilee.