Undefeated boxing champion Floyd Mayweather has never heard of Ronda Rousey, the world’s most famous female mixed martial artist.

Mayweather met with reporters on Tuesday to promote his upcoming rematch with Marcos Maidana in September. During the press conference, Bob Vellin, of USA Today, asked Mayweather if he would fight Rousey, who currently holds the UFC women’s bantamweight title.

But a perplexed Mayweather was unaware of Rousey’s existence. “I don’t even know who he is,” he said.

Several reporters attempted to explain that Rousey is, in fact, a woman, and that she and UFC President Dana White previously discussed the possibility of a fight between her and Mayweather. Mayweather shrugged and said, “I ain’t know who that is.”

In a March interview with Power 106 FM, Rousey, who is undefeated in 10 professional bouts, discussed how she would approach an MMA fight against Mayweather. “I wouldn’t even stand up, I wouldn’t be near him,” she said. “I would just do a little army crawl over there … I would just be skittering after him like the one dude in 'Bloodsport' that was doing the whole monkey crawl fight system. I would do that. I would just bear crawl over there, too low for him to hit me, and tackle him down.”

White took the scenario a step further, suggesting in May that Rousey could defeat Mayweather in anything other than a straight-up boxing match. “You take a street fight, Ronda wins that fight and hurts him badly,” he said. “You do an MMA fight, same result. Boxing match, Floyd Mayweather chews her up.”