Growing up in Dublin, he used to enjoy riding horses -- a hobby that has come full circle with his stint as the so-called "13th Jockey" for Saturday's new Pegasus World Cup
For the trash-talking Irishman, who makes no secret of his lavish lifestyle and desire to make money, it is perhaps befitting that he has become a poster boy -- in varying states of attire -- for what is now the world's richest horse race.
In a series of four promotional films
, the last of which will be shown live on race day, the 28-year-old -- tongue firmly in cheek -- has announced his plan to ride in the $12 million event, calling himself "king of the sport of kings," and drawing parallels between himself and Alexander the Great.
And then there's his desire to get naked.
"I want to ride bareback," he tells his "trainer" -- actually comedian Jon Lovitz.
The third video ends with him apparently unclothed riding around a stable yard.
"Conor, you forgot your socks," Lovitz deadpans.
McGregor won't actually be taking part in the race, which surpasses the $10 million Dubai World Cup as racing's most lucrative prize purse.
There are 12 horses running, whose owners paid $1 million each for the chance to win the $7 million first prize.
Top-ranked Arrogate will go head to head with No. 2 California Chrome, who will seek revenge in his final race before retirement. The 2014 Kentucky Derby winner was chased down by the newcomer at November's epic Breeders' Cup Classic.
On the eve of the race, McGregor told CNN via email that his passion for horses is perhaps as much about making money as it is riding.
"I rode a bit growing up and picked it up again in the 13th Jockey," he explained. "But I've been winning money at the races for years.
Whenever he has time out of the mixed martial arts ring, he likes to go to the race track: "I go all the time. We love to win money at the races still."
As for his own ambitions at the Pegasus World Cup, as ever he is brimming with confidence: "I will be at the top of any sport I desire".