Britney Spears' manager said the 25-year-old singer collapsed at a Las Vegas nightclub New Year's party because she was exhausted, not drunk.

Nearly 1AM on New Year's Eve Britney Spears, dressed in silver Jimmy Choo heels and black sequined Chloe mini dress, suddenly slumped to the floor, the Las Vegas Review Journal reported.

Witnesses said Britney was wrapped in a blanket and carried out of the club, the New York Daily News reported. However, other witnesses told People magazine "She was absolutely not carried out of the club."

Her manager, Larry Rudolph, downplayed the incident Monday, saying Britney Spears had been drinking champagne, but not that much. A source at Pure tells the Las Vegas Review Journal that Britney "had a little too much to drink" and "was assisted out, but she was not carried out."

"She had been traveling all day. She got real tired. It was a late night for her," Rudolph said. "By about one o’clock, she was just done, so we took her out. She was not drunk. She was just tired and falling asleep."

Since filing for divorce from Kevin Federline in November, Britney Spears has made headlines for partying heavily several times, including being pulled from the stage of a Hollywood burlesque club.