We knew it was happening. Now we know when.

Ultimate Fighting Championship (UFC) has scheduled a lightweight championship headliner for its upcoming UFC on FOX 5 event, penciled in for Dec. 8, 2012 at a location to be named, according to a report from USA Today.

And it's the first time a title fight will make it to free TV since Junior dos Santos clowned Cain Velasquez last November.

Fresh off his 155-pound title defense over Frankie Edgar earlier this month, Ben Henderson will put his strap on the line against division number one contender Nate Diaz, who is no stranger to the FOX network, having bested Jim Miller to earn his crack at the crown last May.

If you already have plans for this night, cancel them.

Henderson (17-2) usurped the throne with a unanimous decision win over Edgar at the UFC 144 pay-per-view (PPV) earlier this year in Japan. It wasn't "The Answer" promotion president Dana White was looking for, so the former champ got another chance to set things right.

He was denied at UFC 150 back on Aug. 11.

That means the division moves on without him and with "Bendo" taking over the reigns, his first stop will be in the 209 to face one of the most talented (and entertaining) lightweight mixed martial arts (MMA) fighters under the Zuffa umbrella.

Diaz (16-7) punched his ticket to the Dec. 8 showdown by beating the brakes off Jim Miller at the UFC on FOX 3 event in New Jersey, outstriking the hometown hero before choking him out for his third straight win. Prior to Miller, Diaz put a hurtin' on Donald Cerrone and added Takanori Gomi's arm to his Stockton trophy case.

New champ? Or old shoe?

UFC on FOX 5 will also feature a co-main event between Mauricio Rua vs. Alexander Gustafsson, who battle for a spot in the light heavyweight pecking order. B.J. Penn vs. Rory MacDonald also rounds out the top-heavy network television fight card.

Stay tuned to MMAmania.com for more news and notes on UFC on FOX 5 as they become available.