Speculation Nation!

Note: Today’s column is written by Cristina Gibson while her civic-minded boss man Ted Casablanca is doing jury duty.

Are Nicole and Joel really headed down the aisle? Survey says no...find out why! And while Christina Aguilera shows Sin City she’s so not expecting, what about Sarah Michelle Gellar? We weigh in...

Have you heard all the rampant rumors that Nicole Richie and Joel Madden are engaged? These marital mouthings came, of course, after Nic was snapped wearing a blingin’ bauble on her ring finger recently. Hate to be a nuptial naysayer, but sources close to Joel say it ain’t so.

“Everyone thinks they’re so much more serious than they really are,” says the pal. I also hear that Nic is "the nicest" but is "really quiet” around most peeps. Her brassy style on The Simple Life coulda fooled me. Could it all be an act for the cameras? Or maybe she’s only fierce and feisty around certain people. Like Joel, for ince.

Sources say they were expected at Area last Thursday night but were no-shows at the last minute. The reason? “They got in a huge fight,” an insider says of their absence, “and Nicole wouldn’t let him come.” Crack that whip, honey!

Besides, it’s actually better that the twosome ended up staying home, ‘cause Hilary Duff, Joel’s ex-girlfriend, just so happened to be at Area that night. Whew...awkward sitch averted!

Blond bombshell Christina Aguilera was in Sin City Saturday evening and all aglow, but not in the preggers sorta way, as some rags are proclaiming.

Despite recent reports of Xtina buyin’ baby clothes, sparking rumors the diva could be knocked up with her not-so-hot hubby Jordan Bratman’s bambino, I’ve got a sighting that suggests otherwise. At Pure Nightclub, where Christina-cakes celebrated after her concert, she was seen sippin’ chardonnay with her girlfriends. Everyone knows potentially preggo peeps don’t (or, at least, shouldn't) drink. Plus, Ms. Aguilera’s physique was in fine form...no way was she hiding a bump under her slinky gray dress!

Now, those suspicious-lookin’ pics of Sarah Michelle Gellar’s protruding tummy in Mexico are a whole other story. Sarah’s always been svelte and slender, which makes me think her belly bulge is from a bun in the oven, not a few too many burritos. Plus, she was wearing a very loose, flowy frock when I ran into her at the Elton John Oscar party. So, I rang her agent to get the skinny. "No comment," I was told first. "It's not true," they then added. Hmmm...sounds fishy. Stay tuned.

Leonardo DiCaprio, snuggly with his on-and-off girlfriend, Bar Refaeli. The cozy couple was spotted at the Gig in Hollywood Monday, where they couldn’t keep their paws to themselves. Leo, in a blue pullover sweater and signature baseball cap, was huggin’ his honey from behind and kissing her ears as they watched the band. More platonic twosomes included...

Haylie Duff and Ivanka Trump, in line together for the little girls’ room. Thursday night at Area. Ivanka looked cute in a white dress, according to my sink spy. Not so cute was the fact that she had a friggin’ bodyguard with her! Who does she think she is, an Olsen twin, or something? Raising eyebrows elsewhere was...

Eric Balfour, spotted at Mood Saturday night. The Texas Chainsaw Massacre star was wearing an odd pin that read “Does this d--k in my mouth make me look gay?” Wonder what his attached-at-the-hip girlfriend thought of his accessory. Another oddball out and about: Steve-O, smoking a smelly substance out of a pipe at the same place.