Trump's car? It's just another set of wheels to Larry

Larry, the 10 Downing Street cat, sits underneath The Beast, US President Donald Trump's armoured Cadillac, in London. Photo / Getty Images

WATCH: Larry the cat, chief mouser to the Cabinet Office at No. 10, spent a bit of his morning inspecting, or just napping, under one of the US president’s limousines during the president's state visit in London. pic.twitter.com/DMzGLfyLVv

— NBC News (@NBCNews) June 4, 2019

One beast under another triggered a diplomatic incident in London.

Larry the Downing Street cat, perhaps the most famous executive feline since the Clintons' Socks, took shelter from the rain under US President Donald Trump's armoured limousine, nicknamed "The Beast," and refused to move, NBC reporter Bill Neely said on Twitter.

It wasn't immediately clear whether Larry's presence halted Trump's movement during his tenuous three-day visit to the United Kingdom.

Earlier, the cat appeared in a photo of Trump and Prime Minister Theresa May in front of 10 Downing St, the prime minister's residence.

This is not Larry's first rodeo. He has been a fixture around No. 10 since 2011, when he was brought in to hunt rats after one scurried outside during a live BBC broadcast.

But those duties were short-lived. Larry's duties as "chief mouser" ended in 2016 when he was sacked for sub par performance.

Yet Larry's influence looms large on social media, and he temporarily stole the spotlight from Trump's visit, which has included protests using the nappy-clad "baby Trump" inflatable balloon.

"BREAKING: anti-Trump demonstrators fail to stop @realDonaldTrump motorcade, but @Number10cat does," the BBC's Jon Sopel wrote.

Huge security issue as Larry the Downing St. cat shelters under Donald Trump’s limo ‘’the Beast’ & refuses to move. #TrumpinUK pic.twitter.com/i9w4B6w8FK

— Bill Neely (@BillNeelyNBC) June 4, 2019

Larry sleeps in the street before the arrival of US President Donald Trump in central London. Photo / AP

The red carpet is rolled out outside 10 Downing Streets as Larry watches from a window ledge before the arrival of US President Donald Trump. Photo / AP