The worst-kept secret in UFC history was finally revealed; UFC President Dana White confirmed that former UFC champion Chuck Liddell (20-5 MMA, 15-4 UFC) will face former PRIDE title-holder Wanderlei Silva (31-7-1 MMA, 1-2 UFC) at UFC 79 on Dec. 29.

The pay-per-view event takes place at the Mandalay Bay Events Center in Las Vegas.

White made the announcement during a spot on Tuesday night's "Scream 2007" special on Spike TV.

The one-time cross-promotion mega-fight, which had been promised a few times over the past couple years (most recently at UFC 61), never came to fruition because UFC and PRIDE officials couldn't work out the details. However, owners of Zuffa LLC (the UFC's parent company) purchased PRIDE earlier this year, signed Silva to a contract, and then scheduled him to fight at UFC 79.

Liddell was the likely opponent -- until a split-decision loss to Keith Jardine at UFC 76 in September appeared to temporarily derail the idea. However, despite both fighters coming off back-to-back losses (Liddell to Quinton Jackson and Jardine; Silva to Mirko "Cro Cop" Filipovic and Dan Henderson), the bout remains one of the most-anticipated in MMA history, and UFC officials booked the fight anyway.

MMAjunkie.com spoke to Silva over the weekend during Cincinnati's UFC 77 event, and the Brazilian confirmed he would be fighting Liddell. White, though, remained tight-lipped about the fight, saying only that the two fighters would face off sometime "soon."

Now officially booked, the fight will take second billing to a main event between UFC welterweight champion Matt Serra and former champ Matt Hughes.