Floyd teaches the Biebs.
"Training and having a good time with @justinbieber," the 37-year-old tweeted after the lesson.
Mayweather's former pal 50 Cent actually explained the Justin-Floyd connection to MTV two years ago.
"Justin is also a Floyd fan," the rapper revealed. "They love the sport. A lot of people like it and haven’t actually made contact or received anything to make them feel like it was cool or comfortable enough for them to come. When it actually happens and it goes down like that, it feels good. When they get a chance to see different genres, different people, everybody's excited. Floyd's daughter, Yaya, she saw half the fight, the other half she was looking at Bieber."
Fourteen-year-old Iyana's Twitter avatar is even a photo of her and Justin.
So… who do you think the Biebs was thinking about when he was throwing those punches?