It certainly wasn't love at first sight. In fact, not so long ago they didn't like each other very much.
"I don't hate the man," Elon Musk tweeted in July 2022, "but it's time for Trump to hang up his hat & sail into the sunset."
The Tesla and Space X founder's comment was prompted by a profane Donald Trump insult - put simply, calling Mr Musk a liar. Trump accused Mr Musk of lying to him about who he voted for in the last presidential election.
"Elon is not going to buy Twitter," Trump crowed to a rally crowd in Alaska.
Mr Musk did, of course, buy Twitter several months later - and he went on to endorse Trump’s Republican arch-rival, Ron DeSantis. The Florida governor even launched his presidential campaign with a glitch-ridden chat on Twitter Spaces.
But over the last few months the relationship between Mr Musk and Trump has not just thawed – it has reached a positively warm and steady simmer.
On Monday, Trump returned to Twitter/X after a year-long hiatus, hours before he and Mr Musk were due to sit down for what many expect to be a convivial chat streamed on the platform.
Both men will be hoping the conversation reaches an audience beyond the hyperactive paid-for users who dominate X discussion these days – and that it will be free of the technical glitches that overshadowed Mr DeSantis's ill-fated campaign.
The relationship between the tech tycoon and the Republican nominee has been a while in the making.