The lyrics addressed former president Barack Obama, called out "mask wearers", called coronavirus the "Wuhan Flu", and was blatantly racist towards Chinese and Japanese people.
The notorious prankster, responsible for Borat and Ali G, left members of paramilitary group Three Percenters red faced-after sneaking into one of their Washington events in costume.
Cohen's prank was praised online, especially as the crowd sang back what the organisers admitted were "racist and divisive" lyrics. In the clip below, Cohen gets up on stage dressed as a bluegrass singer and begins belting out a pretty obscene song.
Actor and comic Sacha Baron Cohen - famed for his disguises and stunts - added to his repertoire over the weekend in outrageous fashion.
Baron Cohen was honoured a year ago by the Anti-Defamation League because of his record of using humour to fight hate, including through his Showtime series "Who is America?" which satirises American politics.
The group says on its website that it is "a national organization made up of patriotic citizens who love their country, their freedoms, and their liberty".
Cohen had his own security set up at the show, and they prevented the plug from being pulled, Forrest Gump-style.
The Washington state news outlet The Olympian reports that Baron Cohen crashed the rally of the alt-right militia group the Washington Three Percenters while in disguise.
James Blair, a libertarian Yelm City Councilman who was there for the rally, wrote on Facebook, "He came onstage disguised as the lead singer of the last band, singing a bunch of racist, hateful, disgusting shit".
TMZ reported that at some point the crowd turned on Baron Cohen, who was whisked into a waiting ambulance by his security and driven away.
Apparently, his security guards had blocked the event organisers from stopping him.
Cohen has a long history of poking fun at the far-right and US conservatives on his TV stunt show.
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