Donald Trump's original political guru Steve Bannon revealed that Elon Musk's attempts to gain access to secret briefings on war plans ultimately resulted in the end of his White House bromance.

Bannon - whose influence during Trump's first term compares to 'First Buddy' Musk in the second - has labeled the Tesla billionaire as an elitist outsider and interloper in a political movement he helped shape from the ground up.

In an explosive story about Musk's White House fallout, Bannon says that the alliance ended the moment Trump was prevented from showing Elon Musk the Pentagon's plans for a hypothetical war with China.

'You could feel it. Everything changed. The fever had been broken,' Bannon told The Atlantic.

In late March, the president initially disputed claims by the 'fake news' that Musk was being allowed a glimpse at plans for a hypothetical battle ahead of his visit to the Pentagon.