Rumors are running rampant that someone got Jennifer Aniston pregnant.

The National Enquirer reported earlier this week that Aniston, 38, is expecting and speculated that the father could be either Vince Vaughn, Paul Sculfor or former Sex and the City hunk / Rosario Dawson boyfriend Jason Lewis.

Evidently Steve Bing was not in the running to knock Jen up. Our bets would have to be on Paul Sculfor, her sometime boyfriend throughout 2007 who was the subject of rumors involving a pregnant Jennifer Aniston way back in July.

Jennifer Aniston: Pregnant? No. Happy? You know it!

But according to Jennifer's PR rep, who denies it, we can leave the baby making to Jamie Lynn Spears, Jessica Alba and Jessica Sierra, not Jennifer Aniston.

"Jennifer is not pregnant," the rep said.

And it's a good thing, too: An eyewitness reports that the former Friends star not only got her hair colored, but sipped a martini at a Christmas Eve dinner with her pals, Courteney Cox and David Arquette, at Mastro's in Beverly Hills, Calif.

Jennifer Aniston photos such as the one above show the star "is in a great mood," a source on the scene tells Us Weekly, despite not having a date and "leaving alone" after the Christmas dinner. "There's no drama, and that's why she's happy!"