With a smile he told members of the press that the name of his son X Æ A-Xii "sounds like a password."
Musk and musician partner Grimes initially named their son X Æ A-12 Musk which is supposed to be pronounced "Ex Ash A Twelve".
The baby was born on May 4. Later that month, the kid's name was changed to 'X Æ A-Xii', apparently to avoid violating California naming laws which allow the use of only the 26 letters of the English alphabet, besides hyphens apostrophes.
The interesting incident when Musk appeared to forget his son's name momentarily occurred during his visit to the Gigafactory in Berlin.
In a video of a press conference that has now gone viral, Musk looks confused when an interviewer asked him "how is X Æ A-12?"
Unable to understand the question at first, he asked the interviewer to repeat. He laughed out loud when he understood the question.
"Oh, you mean my kid. That sounds like a password," he said.
Musk even added that the bay boy was doing fine.
"He's great. I think next time I'm going to bring him," Musk told the interviewer, according to a report in MailOnline on Friday.