The caption is a reference to the Netflix series The last kingdom, which Grimes joked about a week earlier, when showing off the child’s medieval haircut in his Instagram stories.
“I’m not sure if the haircut was good, but he’s a Viking now,” she wrote at the time. “Haircut inspired by the latest Netflix realm that is a masterpiece.”
In another Instagram post, Grimes shared a photo of him lovingly embracing X Æ A-XII, who looks at what appears to be a statue of the futuristic robot Maschinenmensch from the 1927 film Metropolis.
“Tell me about the waters of your home world”, Grimes caption the image, citing the science fiction novel Dune.
The independent pop star and the CEO of SpaceX and Tesla welcomed their first child in May 2020, after nearly two years of dating.
See Grimes with X Æ A-XII here and Musk next to his son On here.