Grimes has criticised former partner Elon Musk’s decision to bring their son to an Oval Office news conference.
The 36-year-old singer, who has had an on-off relationship with Mr Musk since 2018, apparently only learned via social media that he had taken X Æ A-12 – or X for short – to the briefing with Donald Trump on Tuesday.
In response to a comment on X about her son being “very polite”, Grimes said: “He should not be in public like this. I did not see this, thank u for alerting me. But I’m glad he was polite. Sigh.”
Mr Musk, 53, carried the four-year-old on his shoulders as he spoke to reporters about his role as the head of the Department of Government Efficiency (DOGE).
X Æ A-12 also stood beside his billionaire father and Mr Trump as they spoke, at one point appearing to attempt to address the president as Mr Musk answered questions.
He also interrupted his dad at times as he was quizzed over accusations he is orchestrating a “hostile takeover” of government in a non-transparent way.
While photographers took pictures, Mr Trump said: “X are you ok? This is X and he is a great guy, high IQ. A high IQ individual.”
Read more:
Elon Musk’s X to pay Trump $10m compensation
Sky News’ correspondents give views on Trump’s call with Putin
X’s parents have previously explained the meaning behind his name, breaking it down into its component elements.
Apparently, “X” represents the “unknown variable”.
“Æ” is the “elven spelling” of “Ai”, which means love in Chinese – and is also an acronym for artificial intelligence.
And the “A-12” is their “favourite aircraft”.
X is one of three children Mr Musk and Grimes share, alongside his younger siblings Exa Dark Sideræl and Techno Mechanicus, or Tau for short.
The Tesla owner is father to 12 children but lost his firstborn child from sudden infant death syndrome (SIDS) when he was just 10 weeks old.