Foreign politicians, celebrities and Twitter users were incredulous, amused and a little worried, after Britain’s new Prime Minister Theresa May appointed foul-mouthed Boris Johnson as her new top diplomat and the head of spy agency MI6.

The former mayor of London has a long track record of making racist, vulgar and insensitive comments about foreign leaders, such as when he labelled Papua New Guineans "cannibals," or when he wrote a poem about the president of Turkey having sex with a goat. Johnson has also compared Hillary Clinton to "a sadistic nurse in a mental hospital," and once suggested that Barack Obama has an "ancestral dislike" of the U.K. because he is "part Kenyan."

Prime Minister May appointed Johnson as Foreign Secretary on Wednesday, giving the former "Brexit" crusader a key role in his country's exit from the European Union. That might prove a difficult task for Johnson, who as recently as last May compared the EU's unification goals to those of Napoleon Bonaparte and Adolf Hitler.

Some foreign politicians offered the usual congratulations following Johnson's appointment, but others were not so enthused.

In the U.S., for instance, State Department spokesperson Mark Toner cracked an amused smile when he was informed of the appointment by a reporter at a news conference.

Carl Bildt, the former prime minister of Sweden, said on Twitter that he wishes the appointment was a joke.

Jean-Marc Ayrault, France's foreign minister, said in a French radio interview that Johnson "told a lot of lies" during the Brexit campaign, adding: "Now it is him who has his back against the wall."

British television showed footage on Wednesday of a sign posted on a fence in Johnson's neighbourhood, which read: "Sorry world."

A number of celebrities also sounded off on the appointment. "Phew!" tweeted Ricky Gervais. "Just when Britain was starting to become a laughing stock around the world, Boris Johnson is appointed foreign secretary."

"Please tell me the Boris thing is not true," tweeted Lily Allen. "I can't even."

Cher attacked Johnson in a string of mostly-capitalized tweets, including one in which she mocks him and former Australiam PM Tony Abbott as "Twiddle Dumb and Twiddle Dumber."

Many Twitter users wondered if the Johnson appointment was an example of British humour.

Others noted that Johnson, in his new role, will also be in charge of MI6, the British Secret Intelligence Service. "If James Bond were real," one person pointed out, "He'd take orders from Boris Johnson."

Some Brits claimed they will move to Canada now that Johnson is in power, echoing a promise some have made in the U.S., if Donald Trump is elected president.