When Elon Musk left the White House just over a week ago, his friendship with Donald Trump seemed as strong as ever.
At an announcement in the Oval Office, the American President thanked Mr Musk for his brief stint helming the Department for Government Efficiency (Doge) and said "Elon is really not leaving."
The two men had been together regularly since Mr Musk joined the President on the campaign trail last year, and just weeks ago he wore a cap which read “Trump was right about everything” at a cabinet meeting.
Under the surface, however, the relationship between the two men was growing increasingly tense - culminating in the spectacular falling out of the last 24 hours on the world’s biggest stage.
Mr Musk had found himself ostracised from Trump’s inner circle in the West Wing. Another factor was Trump's decision to pull his nomination of Jared Isaacman, Musk's hand-picked candidate to be NASA administrator.
Most significantly, Mr Musk was highly critical of the President’s “Big Beautiful” tax and spending bill - and increasingly vocal about his views after his departure.
At a private meeting at the White House on Wednesday, Trump expressed confusion and frustration about Mr Musk's attacks on the bill, according to two officials familiar with the matter.
He held back, the officials said, because he wanted to preserve the Tesla owner’s political and financial support ahead of the midterm elections.
By Thursday afternoon, the President’s mood had shifted. He had not spoken to Mr Musk since the attacks began and was fuming over what one White House aide described as a "completely bats***" tirade by the Tesla CEO on X, his social media platform.
Mr Musk had blasted Trump's tax bill as fiscally reckless and a "disgusting abomination." He vowed to oppose any Republican lawmaker who supported it.
The bill would fulfill many of Trump's priorities while adding, according to the Congressional Budget Office, $2.4 trillion to the $36.2-trillion U.S. public debt. Privately, Trump had called Mr Musk volatile. On Thursday, he told his team, it was time to take the gloves off.
At an Oval Office meeting with the German Chancellor Friedrich Merz, President Trump told the press he was “very disappointed” with Mr Musk’s actions.
The relationship deteriorated further when Trump went on to post on Truth social: "The easiest way to save money in our budget, billions and billions of dollars, is to terminate Elon's government subsidies and contracts."
The X owner was quick to respond on the website, claiming to his 220 million followers that Trump and the Republicans would have lost last November’s election without his help. Mr Musk donated $300 million to the campaign.
In an extraordinary move, Mr Musk then called for the President’s impeachment.
He also claimed to be dropping the “really big bomb” by saying, without evidence, that Trump appears in unreleased documents relating to the dead sex offender Jeffrey Epstein.
Despite weeks of tensions between Mr Musk and others on Trump’s staff, White House officials were reportedly stunned by the speed at which the two billionaires’ relationship collapsed.
One insider said: “It caught the President and the entire West Wing off guard.”
The falling out has seen Tesla’s stock price plunging by 14% - wiping out around $150 million off its value.
With the pair now seemingly irreconcilable, both face problems ahead as a consequence.
For Trump, losing Mr Musk's backing threatens his growing influence among tech donors, social media audiences, and younger male voters - key groups that may now be harder to reach. It could also complicate fundraising ahead of next year's midterm elections.
For Mr Musk, the break risks an intensified scrutiny of his business practices that could jeopardize government contracts and invite regulatory probes, which might threaten his companies' profits.
In a statement, the White House called the breakup an "unfortunate episode from Elon, who is unhappy with the One Big Beautiful Bill because it does not include the policies he wanted."
