The public and the media were not allowed to attend the UFC Fight Night card in Las Vegas.
UFC president Dana White said Tuesday that he wanted to give the media a night off, despite the company's refusal to give a reason for the closing.
According to the women's strawweight contender, who is fighting in Saturday's main event, the reason for the closing is Meta chief executive officer Mark Zuckerberg.
At a media day in Las Vegas, she said she understood that the closing was linked to Facebook.
The entire event was rented out by Mark Zuckerberg. I don't know if he will have friends or not, but I know he will be there. It's going to be very, very private from the person who wanted a main event.
I'm looking forward to it. That makes me want to perform better. Everyone is watching TV, but for Mark and anyone else who is there, put on a show. We are going to give a show if that is what they want to see.
The UFC told its regular media members that there would be no press credentials for the card. The event is not open to the general public.
White maintained Tuesday that there is no big secret behind the decision.
The founder and CEO of Facebook made headlines earlier this month when he posted a video of himself doing MMA drills.