Elon Musk and Grimes have already explained what their baby boy's name means—but the pronunciation of it seems to still be a sticking point with the new parents. People reports that Musk appeared on Joe Rogan's podcast Thursday, and the Tesla/SpaceX CEO was all too happy to give his girlfriend credit for coming up with the newborn's unusual moniker of X Æ A-12. "She's great at names," Musk gushed. CNN notes that Rogan then inquired how to say the name, to which Musk replied: "I mean, it's just 'X,' the letter X. And then, the Æ is, like, pronounced 'Ash.' And then, A-12, A-12 is my contribution."
But the two appear to have a "difference of ... opinion" on this matter, per Vanity Fair. Grimes also weighed in on the pronunciation on Thursday, and her version was slightly different than Musk's, specifically regarding the "Æ" sound. "It's just X, like the letter X," she wrote in reply to a fan's inquiry on Instagram. "Then A.I. Like how you said the letter A then I." At any rate, the two seem to be over the moon at their first child together, with Musk—who has five other boys from a previous marriage—telling Rogan "it's better being older and having a kid." The 48-year-old adds: "I appreciate it more. Babies are awesome." X Æ A-12 is 32-year-old Grimes' first child. (A previous Musk appearance on Rogan's podcast was a little more controversial.)