Kimbal Musk and his wife Christiana are opening up about the SpaceX founder and X owner

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Kimbal Musk is sharing a glimpse of what it’s like to be Elon Musk’s brother.

In a wide-ranging and rare interview with The Times, the chef, businessman and philanthropist opened up about growing up as the middle child in the Musk family — and revealed that as a Tesla board member, he sometimes butts heads with his billionaire brother.

“This is a bit nuts and bolts-y — excuse the pun — but we actually had a debate about manufacturing and how we get the costs down,” Kimbal, 51, told the U.K. publication about a recent middle-of-the-night interaction. “And we just fundamentally disagreed on how to do that. We had a conversation and it was very heated. At one in the morning I had something more to say so I thought, ‘I’m just going to call him.’ ”

“He and I have very different ideas on how to build a business,” he added.

Yet despite their occasional differing perspectives, the Musk brothers — who “literally used to get into fistfights” when they were children, according to Kimbal — always make up quickly.

“We might be angry as heck in the moment, and then five minutes later we want to watch a movie together,” he shared.

Christiana, the Kitchen Restaurant Group founder’s wife of six years, agreed with the assessment.

“Kimbal challenges Elon and disagrees with him more than anyone, but in a container of, ‘I love you, you’re my brother. But I don’t agree with you…’ ”  she said. “They have different world views but at the end of the day they are both just giggling children. They have the most insane laughter attacks with each other.”

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Through the years, the SpaceX founder and X owner, 53, has made time amid his busy schedule for his younger brother.

The couple, who had four separate wedding ceremonies in 2018 — including one where Norman Lear and his wife Lyn officiated — look back fondly at the ceremonies, where Elon, who has been married twice, was the best man three times.

“All three he came in at the very last second, when we didn’t think he was going to make it,” Christiana said. “You know how everyone [at weddings] reads Kahlil Gibran’s On Marriage or On Love? Well, Elon read On Pain. And then looked us in the eye. And it was like, ‘Wow, it’s really powerful actually.’ ”

The couple, who each were previously married before tying the knot, now live in Boulder and share four children — and they look after Elon as well, Christiana said.

“We stay in an Airstream [when we visit],” Christiana said about visiting where Elon lives, in a 1,000-square-foot home in South Texas. “We still managed to throw a 50th birthday for him at Starbase, campout-style, but it’s harder now. He’s different. Elon doesn’t think about food or meals. There’s a lot of chaos. Kimbal loves to nourish him and makes him three meals a day and provides a calming, loving environment.”

Kimbal added, “I don’t even know how he eats [when I’m not there].”