UFC President Dana White announced that tickets for the Oct. 29 event at the Mandalay Bay Events Center sold out within hours of going on sale Friday.
The sell out comes only days after contender Nick Diaz was dropped from his UFC welterweight title shot against Canadian Georges St. Pierre, and replaced by Carlos Condit.
White was furious at Diaz for failing to attend promotional news conferences in Toronto and Las Vegas this week, and temporarily cut the Strikeforce welterweight champion from the card.
On Thursday it was announced Diaz would replace Condit on the undercard in a fight against B.J. Penn.
"It's been a crazy few days here at UFC, but there's no doubt that UFC 137 is going to be an incredible card," said White in a statement.
"GSP is on his way to becoming the best welterweight of all-time, but Condit wants that belt. He's knocked out his last three opponents and couldn't be more fired up for this fight. Plus, we've got BJ Penn taking on Nick Diaz in what could be one of the most intense fights of the year.”