Carl Frampton said he was extremely appreciative of the efforts people had gone to support him in Las Vegas.
The featherweight champion told BBC Sport he knew a man who had sold his car and bought a cheaper one to raise funds for the trip.
He said there was a fan travelling from Australia who had also been at his fight with Scott Quigg in Manchester.
“They’re coming from all over the place,” he said. “I’m being supported from far and wide.
“I understand it’s difficult for people to get here. It’s expensive. It’s not easy to get out to.
“It just makes me more appreciate of the effort people are putting in to get out here.”
He told The Telegraph Northern Ireland’s sporting stars were feeding off each other’s success.
The 29-year-old said: “We’re all flying at the moment.
“Since I’ve been alive, it’s been the best in terms of sporting achievements. It’s the best football team since I’ve been alive.
“You’ve also got Rory McIlroy, on his day easily the best golfer in the world. Jonathan Rea doing his thing on the motorbikes, just like the Dunlops had done before.
“It’s huge. We’re all taking inspiration from each other, thriving off each other. Sport is the thing that’s seeming to bring us all together.”
Carl Frampton takes on Leo Santa Cruz on Saturday night in Las Vegas. The fight is due to start at 4am on Sunday GMT. It is available on Sky Sports 1 at no extra charge.