McGregor is a known supporter of the former US president, who he called “quite possibly the USA Goat [greatest of all time] a day after Joe Biden took office.
"Phenomenal President," the Irish fighter tweeted in January. "Quite possibly the USA Goat [greatest of all time]. Most certainly one of them anyway”.
Mr Trump’s attendance was reportedly confirmed by UFC president Dana White, who told a TSN reporter, Aaron Bronster, on Wednesday that Mr Trump was among the stars attending the fight on Saturday in Las Vegas.
Justin Bieber, Megan Fox, Kourtney Kardashian, and Machine Gun Kelly are also expected to attend.
Before running for office in 2016, Mr Trump was a boxing promoter for a brief period in the 90s, hosting high profile fights at his casinos, which eventually went bankrupt.
UFC’s president said last year he did not “give a s***” if his organisation lost fans because of his 20-year friendship with the former US president, Business Insider reported.
"I can't say it enough. This guy is such a good friend and such a loyal, amazing guy, man. He's a great guy. A friend of mine for a long time,” Mr White said of Mr Trump.
It is not the first time the former US president has attended a UFC event, after he appeared at an event at Madison Square Garden in New York in 2019, also at the invitation of the UFC president.
The crowd booed and cheered, and on Saturday will be expected to do the same.
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