Taking to their official Instagram account, the couple posted a black-and-white photo of Prince Charles looking down on Archie on the day of his christening.
In the photo, Archie wears a traditional royal christening gown and lays calmly in the arms of his dad, Prince Harry.
“Happy birthday to His Royal Highness The Prince of Wales — Sir, Pa, Grandpa,” they captioned the snap. The Prince of Wales turned 71.
Royal photographer Chris Allerton took the photo at Archie’s christening on July 5, two months after he was born.
The group photo featured Archie’s aunt and uncle, Prince William and Kate Middleton, as well as Prince Charles and Camilla, Duchess of Cornwall, and the late Princess Diana‘s two sisters, Lady Sarah McCorquodale and Lady Jane Fellowes.
The last time Prince Harry and Markle’s baby was seen in public was during their royal tour in Africa.
The six-month-old met with anti-apartheid hero Archbishop Desmond Tutu in South Africa on the trip.
On Sept. 25, day 3 of the royal couple’s tour, the duke and duchess had their firstborn in tow for tea time with Tutu and his daughter, Theresa Thandeka Tutu, in Cape Town.
The family stopped by for finger foods at the Desmond & Leah Tutu Legacy Foundation, which aims to help in the development of youth and leadership and facilitate discussions on social justice.
In video footage first shared on the couple’s Instagram account, Prince Harry can be heard telling Archie: “You get to meet Arch!”
The duchess can be heard describing her son as “an old soul” in more footage shared by the Sussexes.