Elon Musk’s brood just keeps growing.
The Tesla mogul and his on-again, off-again partner, Grimes, secretly welcomed their second child together, a baby girl named Exa Dark Sideræl, via surrogate in December 2021.
The unusually named tot, who goes by Y, joins Musk’s six other children: Griffin, Xavier, Kai, Saxon, Damian and X.
Meet the billionaire businessman’s kids and their mothers below.
Nevada Alexander Musk
After marrying in January 2000, Musk and Canadian author Justine Wilson welcomed son Nevada Alexander Musk in 2002. Nevada died of sudden infant death syndrome, or SIDS, at only 10 weeks.
Griffin and Xaiver Musk
After losing their firstborn, Musk and Wilson turned to IVF to grow their family. She gave birth to twin sons Griffin and Xavier Musk in April 2004. The boys are now 17.
In June 2022, Xavier filed a legal request to change their name to Vivian Jenna Wilson, taking the last name of the teen’s mom.
The filing lists their reason for the name change as “gender identity and the fact that I no longer live with or wish to be related to my biological father in any way, shape or form.”
Kai, Saxon and Damian Musk
The former couple also used IVF to welcome triplet sons Kai, Saxon and Damian in January 2006. The trio are now 16.
Musk and Wilson divorced in 2008 and share custody of their five sons.
X AE A-XII Musk
After two marriages to “Westworld” star Talulah Riley and a brief relationship with actress Amber Heard, Musk started dating singer Grimes in May 2018. She gave birth to their son, X AE A-XII, in May 2020. X is now 1.
X was originally named X Æ A-12, but “Æ” and “12” violated California law for not being part of the English alphabet, forcing his parents to change his name.
Page Six exclusively reported in September 2021 that Musk and Grimes had broken up.
Exa Dark Sideræl Musk
Grimes revealed in March 2022 that she and the SpaceX founder had welcomed his first daughter, Exa Dark Sideræl Musk, via surrogate in December 2021. She was given the nickname Y after their other child being named X.
Grimes referred to Musk as her “boyfriend” in the bombshell Vanity Fair interview, though she called their relationship “fluid.” Hours after the cover story was published, however, she tweeted that they had since split again.