Bieber showed up at Mayweather, Jr.'s press conference for his big fight with Roach's longtime client Manny Pacquiao in Los Angeles on Wednesday (11Mar15) and posed for photos with the champ - something that amused the top trainer.

Speaking after the event, Roach chuckled, "Justin Bieber, give me a break. He (Mayweather) couldn't get a better guy than that...? I think his (Bieber's) audience is more like 13 year olds."

But Mayweather, Jr. insists having Bieber in his corner is a good thing: "Justin Bieber is a cool guy. I like Justin Bieber. His music is remarkable."