It was enough to raise goosebumps on the legs of an impartial observer - and more arousing than McGregor could handle.
The cult hero was seemingly so moved by the outpouring of affection he walked to the stage with an erection.
Any chance of it remaining the little Irish elephant's trunk in the room disappeared when Mayweather spotted his rival's boner - and began pointing at it and taunting.
McGregor was aware and tried to adjust his Calvin Kleins when he stepped on the scale, but it's not the first time he's weighed in stiff.
That's what pure, unadulterated adoration can do to a man.
McGregor would have ripped a hole in his shorts if he could have seen the throng that gathered at the bottom of the escalators at T-Mobile Arena.
Fans of all ages were in full voice as they continued the party outside the stadium.
"There's a saying, you'll never beat the Irish. You can't beat us. We roll in and take over wherever we want. Las Vegas is Ireland now," McGregor said.
They certainly provided a better atmosphere than what was on offer inside.
It wasn't that hip hop performers like YG and Cardi B didn't perform well, it's just they had the wrong audience.
Floyd Mayweather Jr. and Conor McGregor during weigh-ins. Photo / AP
All that gangster stuff might fly with Mayweather's regular crowd, but that's not who was in attendance.
Still, it was a fun vibe as a man selling beer yelled "Let's get drunk! Long live Ric Flair!" and actor Michael Rapaport fired up the Irish with his pro-Mayweather pick.
"I got 'Money May' all day," Rapaport said. "(McGregor) should be focused. Focused on getting that ass kicked."
NBA stars Draymond Green and Paul George popped in and were also riding with Floyd.
"I think Floyd is going to have a lot of teaching moments," new Thunder star George said.
"I think Floyd is going to pretty much dominate this fight. I don't understand how people are riding with someone who never boxed beat someone who's never lost at boxing."
"I'm excited to be here and see Floyd dominate," Warriors two-time champ Green added.
"There's a highlight of me playing football at Michigan State. I went and played in the spring game. I thought I knew how to play football. It didn't work out."
Those opinions were certainly the minority in a green, white and orange-dominated crowd, but Mayweather wasn't bothered by the lack of overall support.
"The fans can't fight for you," he said. "It comes down to the two competitors."
