LAS VEGAS » B.J. Penn tipped the scales at 168 pounds, easily making weight for tonight's UFC welterweight title fight against champion Georges St-Pierre in the main event of UFC 94 at the MGM Grand Garden Arena in Las Vegas.

St-Pierre weighed in at 170 pounds, making the first fight between UFC champions in different weight classes official.

"I'm ready. There's nothing left to say," Penn said after he made weight. "Let's fight. Let's go."

Penn is 13-4-1 and trying to become the first man to hold two UFC titles at the same time. St-Pierre sports a 17-2 record.

"I've never been so excited," St-Pierre said. "I've never wanted to win so bad."

The pay-per-view begins at 5 p.m. Hawaii time.