Duchess of Sussex Meghan Markle has revealed that she fondly calls her son Archie as "Bubba".

Markle shared the sweet nickname for her nearly five-month-old son during the little royal's first-ever official engagement on Wednesday, reports "people.com".

During the tour, Markle along with Prince Harry met with South African human rights activist Archbishop Desmond Tutu and his daughter, Thandeka Tutu-Gxashe.

In a video from the visit, Meghan is heard calling her son "Bubba."

"Say hello! Hello, hi, Oh, Bubba," Markle said in the video.

After the visit, the couple posted a black-and-white shot of Archie on their Instagram, alongside the caption: "Thank you Archbishop Tutu for your incredibly warm hospitality, Archie loved meeting you!"