In one broad stroke, UFC president Dana White unveiled the expected marquee acts for UFC 152.
If all goes according to plan, the event will see Junior dos Santos defend the UFC heavyweight championship against Cain Velasquez in the headliner, while B.J. Penn would take on Rory MacDonald in the co-main event.
White revealed the news following the UFC on FX 3 post-fight press conference.
Neither of the fights are yet official, however.
The event, scheduled for September 22 in Toronto, does not yet have a host arena, though it is expected to emanate from the Air Canada Centre, the site of last December's UFC 141.
dos Santos-Velasquez would be a rematch of their November 2011 fight which marked the beginning of dos Santos' title reign. He knocked out Velasquez in just 64 seconds before defending the belt in a second-round TKO of Frank Mir at last month's UFC 146.
Velasquez also won on that card, brutalizing Antonio Silva en route to a first-round TKO finish.
The MacDonald vs. Penn fight was a bout essentially booked by the fighters themselves. Last Monday on the MMA Hour, MacDonald challenged the legendary Hawaiian to the match, and within days, Penn accepted the challenge.
Penn briefly retired after his last match, a decision loss to Nick Diaz, but he'll try to produce at least one more moment of glory against the fast-rising MacDonald.