On Tuesday, the billionaire Tesla CEO replied to one follower to reveal that Grimes was in labour.
Four hours later, Musk confirmed that Grimes had given birth to a baby boy, tweeting: “Mom & baby all good.”
The 48-year-old was asked by one follower to reveal the name of his new son.
Musk replied: “X Æ A-12 Musk” and later shared a photograph of the newborn that featured illustrated graphics on top.
The sleeping baby was pictured with the words “Savage” written under his eye among other graphics.
“Congrats!” wrote one follower in response to the photo, to which Musk teasingly replied: “Thanks :) Never too young for some ink haha.”
Grimes hinted that she was pregnant in January with a picture on Instagram that showed her posing nude with a digitally-superimposed image of a foetus visible through her translucent stomach.
Grimes first shared the image with her nipples visible, and replied to an Instagram user’s comment explaining she initially considered censoring the image in line with the platform’s nudity policy, but “being knocked up” is a “very feral and war-like state of being”.
She later deleted the image and re-shared a censored version, still showing the foetus.
The celebrity couple revealed in May 2018 that they had become romantically involved, making their first public appearance at the Met Gala.
Musk has six children with his ex-wife, Justine Musk, to whom he was married from 2000 to 2008.
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