Joe Biden’s immense armoured limousine - nicknamed “the Beast” - got stuck in traffic as it made its way towards Westminster Abbey on Monday morning.
The US President was heading for the Queen’s funeral when the vehicle got held up outside a Pret a Manger.
Mr Biden was seen waving to members of the public, who were shocked to see the US President drive past them near Marble Arch.
Video shows members of the public waving and taking pictures of the President as Met Police officers stood guard.
A member of the Met Police Special Escort Group can be seen on the video racing past the Beast on a motorbike to clear the traffic ahead.
Other world leaders, including French President Emmanuel Macron and New Zealand Prime Minister Jacinda Ardern, are arriving at Westminster Abbey for the Queen‘s funeral in a fleet of buses, Mr Biden was allowed to ride in The Beast.
But commentators quipped that the US President might as well have taken the bus after the video was shared on TikTok.
Mr Biden and wife Jill arrived in London on Sunday ahead of Monday’s ceremony.
On Sunday the couple visited Westminster Hall to pay their respects to Her Majesty as she lay in state.
The US President, a devout Catholic, crossed himself while looking solmenly towards the late monarch’s coffin.
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Mr Biden also visited Lancaster House where he signed a book of condolence.
Belgium’s King Philippe and Queen Mathilde, Spain’s King Felipe and Queen Letizia, Sweden’s King Carl XVI Gustaf and Queen Silvia and the Netherlands’ King Willem-Alexander and Queen Maxima are among those making a humble group bus trip.
But Mr Biden was given a special exemption by the Foreign Office to be taken in his bulletproof limo.
The late monarch met with 13 of the last 14 US presidents during her incredible 70-year reign.
The Queen’s funeral begins at 11am on Monday.