"There are going to be millions of people tuning in that have never seen the UFC before," said White.
"We're going to have to be spending some time introducing people to the sport and laying out some of the rules and things like that."
White anticipates the event will have the largest viewership of any UFC fight in North and South America.
White said the decision to air the Velasquez-dos Santos fight free was made only days ago after many machinations of what the first event on Fox should be.
"We were looking at so many fights. But we wanted to deliver to our fans and kick it off in a real serious way," said White.
"We were kicking so many things around. Do you go with Anderson Silva the greatest pound-for-pound fighter in the world? There were all sorts of fights we were looking at. But the obvious answer was staring us in the face. The heavyweight championship of the world."
Velasquez -- undefeated at 9-0 with eight knockouts -- will face the No. 1 contender Junior dos Santos, who is 13-1.
White says the fight, at Anaheim's Honda Center, will be a full card, though details of who will fight in the undercard and how the rest of those scraps will be broadcast are still being worked out.
"The fans at the Honda Center won't notice the difference. It'll be like any pay-per-view," says White.
"And we'll find a way to broadcast those other fight to the fans."
UFC on Fox comes a week before UFC 139 in San Jose -- which was long rumoured to be the Velasquez title defence.
White says he's excited at the potential affect of a free fight on Fox one week before the Brian Bowles-Urijah Faber battle at UFC 139.
"Having a free fight on Fox leading to a pay-per-view the next week sure doesn't suck," says White.
St. Pierre, Diaz set to face off
The UFC has officially announced Georges St. Pierre's next title fight. The Montreal welterweight champ will take on Nick Diaz Oct. 29 at Mandalay Bay in Vegas. The long-rumoured battle will also feature a welterweight contender battle between B.J. Penn and Carlos Condit as well as Mirko "CroCop" Filipovic taking on Roy "Big Country" Nelson.
Spider spins to top of poll
For the first time, the choice for top pound-for-pound fighter on the planet is unanimous. The Yahoo! Poll of 20 MMA journalists has given the honour to Anderson 'Spider' Silva.
UFC extends deals of trio
Three top contenders have had their UFC contracts extended. Welterweight Carlos Condit, lightweight Ben Henderson and middleweight Michael Bisping have all signed multi-fight deals.
A Brock of malarkey
UFC president Dana White says there is no truth to rumours circulating that Brock Lesnar is on the verge of retiring due to his stomach illness. "Nothing could be further from the truth," said White.