Elon Musk has said a black eye reporters spotted during a farewell to the White House press conference with Donald Trump on Friday was caused by his son punching him while they were “horsing around”. The 53-year-old tech billionaire and world’s richest man had been working in the Trump administration’s Department of Government Efficiency (DOGE) which was tasked with identifying “waste” and making sweeping cuts to the federal workforce.

He’s now stepping back to focus on his companies, including electric car giant Tesla. Musk appeared alongside Trump in the Oval Office on Friday, where the President thanked him for his work. But reporters and people watching the press conference on social media quickly spotted bruising around Musk’s right eye as he stood beside Trump.

Asked about the apparent injury, the Tesla CEO said his son X Æ A-12, also known as X was behind it.

Musk, who also owns tech giants SpaceX and X (formerly known as Twitter) explained: “I was horsing around with my son… I said ‘go ahead and punch me in the face’, and he did.

“It turns out a five year old can punch, actually. I didn’t really feel much at the time.”

Despite his contact coming to an end, the Tesla CEO will seemingly stick around the White House, as Mr Trump said “he would be back”.

Musk has been a passionate supporter of the President’s agenda, and spent nearly $300m (around £222.6m) backing Trump’s successful campaign for a second term.