Even though observers have long speculated that Donald Trump and Elon Musk would eventually fall out, few predicted the speed and ferocity with which their social media feud erupted.
Since Musk pledged his full-throated support for the president following an assassination attempt in Pennsylvania less than a year ago, the political and business interests of the two men have become increasingly intertwined.
In several key areas - including political funding, government contracts and their personal relationships - the two men have come to rely on each other, meaning ending the alliance is likely to be messy.
That complicates the fallout from their rift and ensures that, wherever the row goes from here, they will continue to be linked – and have the potential to hurt each other in multiple ways.
Over the course of the last year, Musk's donations to Trump and other Republicans have been enormous – totalling $290m (£214m) according to the campaign finance tracking site Open Secrets.
