The appointment fulfils a promise Mr Trump made to the tech billionaire after he endorsed him in the race for the White House.

Trump made the announcement on social media, fulfilling a promise during the campaign to give Musk sweeping oversight of federal spending.

These two wonderful Americans will pave the way for my Administration to dismantle Government Bureaucracy, slash excess regulations, cut wasteful expenditures, and restructure Federal Agencies,” said Donald Trump in a statement.