Silva and Belfort gave the fans a preview of what's to come, engaging in one of the most intense staredowns in UFC history before exchanging words and eventually being separated by UFC personnel.
Silva, playing on Belfort's recent assertions that he "wears a mask," in putting on a different persona to intimidate his opponents, took the words literally, wearing a white mask and going nose-to-nose with Belfort before ripping it off and exchanging some words with the former UFC light-heavyweight champion. He and Belfort heatedly went back and forth, with both refusing to back down until being pulled apart.
Both fighters weighed in at the middleweight championship limit of 185 pounds.
Coming off perhaps his career-defining performance in a thrilling comeback win over Chael Sonnen, Silva faces the powerful striker Belfort in a match that is being called the "Fight of the Century" in their home country of Brazil.
"Yesterday I said he wore a mask," Belfort said. "I know him, he's a good man but in the fight he tries to impress and make the fighters afraid of him. That's what he wants, that's not what's going to happen."
Silva, who got a mostly positive reception at his introduction, was booed loudly after the exchange.
"It's no secret what I said," said Silva, who has a UFC record 12-fight win streak. "Vitor talked a lot. You came here to watch a show. That's what you're going to see is a show."
In the co-main event, a smiling Forrest Griffin weighed 205 for his comeback fight after a 15-month hiatus following shoulder surgery. Griffin will be facing former UFC middleweight champion Rich Franklin, who checked in at a light 203 pounds.
Both men are coming off wins. Griffin outworked Tito Ortiz is a split decision at UFC 106, while Franklin essentially retired Chuck Liddell after knocking him out at UFC 115.
In another highly anticipated fight, Jones (206) outweighed Bader (205) by a single pound in a light-heavyweight bout between a pair of rising stars.
Mike Pierce was the only fighter to miss weight on the stage, but MMA Fighting has confirmed Pierce cut the extra pound and officially weighed in at 171 after the televised weigh-ins concluded.
Anderson Silva (185) vs. Vitor Belfort (185)
Forrest Griffin (205) vs. Rich Franklin (203)
Ryan Bader (205) vs. Jon Jones (206)
Jake Ellenberger (171) vs. Carlos Eduardo Rocha (170)
Antonio Banuelos (136) vs. Miguel Torres (136)
Paul Kelly (155) vs. Donald Cerrone (155)
Chad Mendes (146) vs. Michihiro Omigawa (146)
Demetrious Johnson (136) vs. Kid Yamamoto (135)
Gabe Ruediger (155) vs. Paul Taylor (156)
Kyle Kingsbury (205) vs. Ricardo Romero (205)
Mike Pierce* (171) vs. Kenny Robertson (170)
*Pierce weighed in at 172 on stage, but eventually made the required weight at 171.