After originally wanting to name the brand "Notorious" after his nickname, he gave up on a trademark dispute and instead landed on something more personal.
"I come from a place called Crumlin, in Dublin 12," McGregor explained. "It's a place dear to my heart. It's where I learned how to fight, it made me who I am today. It's a place I'm still very much a part of every single day of my life. So, that's where the name came from. It's proper Irish whiskey and twelve is my hometown."
In addition to creating the name, McGregor was apparently directly involved in creating the whiskey's blend, with officials saying he "took a detailed, time-intensive" approach with the formula.
According to Brad Japhe of Forbes, master distiller David Elder was also involved in the creation of the 80 proof liquor after spending years working for Guinness.
McGregor was already listed as the fourth-richest athlete in the world for 2018 while earning $99 million, per Forbes, mostly thanks to his boxing match against Floyd Mayweather. He hasn't competed in a mixed martial arts bout since November 2016 but is set to make his return on October 6 against Khabib Nurmagomedov.
It seems he utilized part of his time off pursuing his other passions outside of the Octagon.