Conor McGregor is without doubt the biggest star in the UFC right now and can write another chapter in his legacy by defeating Dustin Poirier in their trilogy fight at UFC 264.

The Notorious is bidding to avenge his stoppage defeat to The Diamond when he faces the American for a third time in Las Vegas on July 24.

Neither man has fought since their second bout at UFC 257 on Fight Island, which Poirier (27-6, 1 NC) won via a second-round technical knockout after crippling McGregor's right leg with some devastating calf kicks.

McGregor (22-5) has not won a UFC fight since January 2020, where he defeated Donald Cerrone in his comeback fight following a period of inactivity. 

Despite this, McGregor, 32, who has competed at featherweight, lightweight and welterweight, is still arguably the biggest combat sports athlete of all-time and perhaps the biggest sports star in the world, period.

He has legions of fans worldwide who follow him pretty much wherever he goes, with a stand-up fighting style which makes for entertaining fights, and has for years faced whoever is put in front of him.   

However, things may have turned out quite differently, if the UFC had not first turned down the opportunity to sign the Irishman back in 2012.

Last year, McGregor's coach John Kavanagh released details of a rejection letter received in December of that year from UFC matchmaker Sean Shelby, which has recently resurfaced ahead of McGregor's highly-anticipated rematch with Poirier next month. 

Replying to an email from Haraldur Nelson, the father of McGregor's teammate Gunnar Nelson, Shelby, Shelby insisted he was not interested in signing McGregor at the time.  

“If I can use any of your fighters, especially Conor, I will contact you,” Shelby wrote. 

“At the moment, the featherweight division is terribly impacted from so many UFC lightweights moving down in weight.

“So, I’m not looking to sign anyone else for a while, but, hopefully, it will clear up soon and guys like Conor will get the opportunity.”

However, it didn't take long for Shelby to soon change his mind, as less than a month later McGregor became only the second Cage Warriors double champion when he knocked out Ivan Buchinger to add another belt to his collection. 

McGregor's rise to stardom began shortly after making his UFC debut in April 2013 against Marcus Brimage, where he needed little time to knock the American out cold at the Ericsson Globe Arena in Stockholm. 

The rest, as they say, is history. 

Read more: Ian Garry exclusive: Conor McGregor is 'the biggest star there's ever been in the sport'