The unidentified guest of an after-party in the gambling capital said Hilton drank both vodka and tequila during the celebration, an obvious clue she was not pregnant with her first child, People.com reported Saturday.

"She's clearly not pregnant," the unidentified source said.

The heiress was in Las Vegas filming her newest TV series, "Paris Hilton's My New BFF," for MTV.

Hilton had become the focus of multiple pregnancy rumors recently on the Internet since her relationship with Good Charlotte rocker Benji Madden appeared to blossom.

Madden was on hand for Friday's festivities, but People.com said the guitarist spent most of the night with Hilton's sister Nicky and her sister's boyfriend, David Katzenberg.