Hook Ups

We're told Rob Kardashian has been dating none other than Lisa Ann -- the adult film star who headlined the XXX classic, "Who's Nailin' Paylin?" Rob picked up Lisa Ann at the gym right around the time of Khloe's wedding.

Lisa Ann tells us, "Rob treats me like his little teacher and we have a fun sexual relationship that is simple and carefree. He brings out the total cougar in me and I just like to teach him things."

TMZ spoke with Johnson who said, "Now that it is after the fact, I will admit that we were together. We agreed to keep this private because it was the only thing that he could keep private ... we remain close friends."

Johnson claims the two dated for just over a year between 2007 and 2008.

Phelps was rumored to have dated the previous Miss California, Carrie Prejean -- so far, no cell phone video to back that up.

Last year, Robin and his kid's former nanny-turned-wife of 20 years filed for divorce.

His heart will go on.

As you can see by TMZ's Incredible Zoom Technology (IZT), the grainy picture is no more clear after being enlarged than it was when really, really tiny.

TMZ has yet to identify the third person in photograph, who also may or may not be dating Rob and/or Kristen.

This weekend in front of The Ebell theater, a sweaty Ray asked wifey Anna "Are we gonna have sex tonight or not?" -- and was denied faster than Tara Reid at Hyde.

The actor formerly-and-always-known-as Carlton Banks busted out a freestyle rap session at last night's Steel Panther show -- a session that started with the line, "I have been known to f*** some white girls in my lifetime!"

TMZ obtained this video of Natalie inside the "Bad Girls" crib talking about how much she wants the convicted felon -- a dude who she says "might beat Rihanna," but "doesn't beat me."

Clearly, she sets her standards high.

UPDATE: Chris posted the following comment on his Twitter: "WTF!!!! WHAT MOON WAS THIS GIRL ON WHEN SHE THOUGHT OF THIS OUTRAGEOUS LIE>SHE ON TMZ TRYNA MAKE A NAME FOR HERSELF.I DONT KNOW YOU. I TOOK A PICTURE WITH THIS GIRL AT ME A POLOWS SKATE PARTY AND SHE RAN WITH
THE STORY. SHE'S T'D (TIRED). I GOTTA LIMIT WHO I TAKE PHOTOS WIT NOW... some people have motives thataren't positive.."

No word if the two are "officially" dating ... but we're guessing 19-year-old Swifty is just another girl waiting for this piece of underage meat to turn 18.

The woman in the photos is Natalie Nunn, a contestant on the next season of a reality show called "The Bad Girls Club" -- which features women with behavioral issues.

Nunn has been out with Brown a couple times in the last few weeks -- most recently at a roller-skating party on October 16th.

In her bio for the show Nat says she "enjoys cruising in her sugar daddies' expensive cars and painting the town red with her cool celebrity friends."

She has an interesting interpretation of "cool."

UPDATE: Brown just Twittered on the subject: "Tmz..omg.... U guys have nothing better to do. And by the way. I don't mess wit that girl."

The actress -- who's made out with Penelope Cruz and Christina Ricci before for work -- went girl-on-girl again yesterday after offering up her lips for the OneXOne celebrity auction in San Francisco.

The result: A steamy, 25 second smoochfest with the mystery woman who paid top dollar.

We got Deryck drowning his sorrows in girlfriend Hanna Beth Merjos' mouth at Tattoo Mania in Hollywood last night, the two looking quite cozy as they kissed and writhed all over a table inside.

Avril's divorce docs say they separated on September 4th -- boy moves fast.

The dude with more notches on his bedpost than Samantha Jones appeared on "It's On with Alexa Chung" yesterday -- where he admitted threesomes are more common in his life than twosomes.

In related news, Gerard Butler is still officially "The Man."

The "Dancing with the Stars" pro -- who just broke up with ex-fiance Maksim Chmerkovskiy -- was all over the baseball player last night during the Steel Panther show at the Key Club.