Elon Musk and his ex-girlfriend Grimes have welcomed their second child.

By Adelaide,

Singer Grimes and Tesla CEO Elon Musk have welcomed their second child together, a daughter named Exa Dark Sideræl Musk. The singer confirmed that she and Elon had become parents again in an interview with the new issue of Vanity Fair magazine.

Grimes, who also shares 22-month-old son X Æ A-Xii, with Elon confirmed that the pair welcomed their daughter via surrogate.

Grimes described Sideræl as the “more elven” spelling of ‘sidereal’ which she defined as “the true time of the universe, star time, deep space time, not our relative earth time”.

Despite splitting up last September, Grimes revealed that she still considers Musk to be her “boyfriend” but describes their relationship is “very fluid”.

The pop star, whose real name is Claire Boucher, said: “There’s no real word for it. I would probably refer to him as my boyfriend, but we’re very fluid.

“We live in separate houses. We’re best friends. We see each other all the time… We just have our own thing going on, and I don’t expect other people to understand it.

“This is the best it’s ever been… We just need to be free.”

Grimes also hinted that she and Elon want to have more children