KATY PERRY PARTIES WITH RUSSELL BRAND LOOK-A-LIKE: KATY PERRY'S impending divorce apparently wasn't enough to keep her from partying on New Year's Eve with friends and flirting with a so-called 'mystery man' described as a "dead-ringer" for estranged hubby, RUSSELL BRAND.

According to the New York Post's source, a "happy looking" Perry "spent most of the night dancing and laughing with friends. At one point, she was talking to a guy with long hair down to his shoulders in the hallway. They were talking for a while. She was smiling and leaning up against wall."

“After midnight Katy and a male friend got on the dance floor, twirling each other around and dancing holding hands. She looked like she was having a great time,” the source added.

NO PRENUP BETWEEN KATY PERRY AND RUSSELL BRAND: As we closed in on Christmas, all the tabloids were trying to suggest that KATY PERRY was pregnant. Turns out they were going 180 degrees in the wrong direction because last Friday Brand filed for divorce.

As for what broke them up, no one really knows at this point. One gossip source claims Russell was jealous of Katy being the bigger star, and would, quote, "pick her to pieces over the most trivial things." Another says they started bickering soon after the wedding because he gave up partying and substance abuse years ago, while Katy loved to go out.

MAN ARRESTED AFTER KNOCKING ON LINDSAY LOHAN'S DOOR: A 64-year-old man knocked on LINDSAY LOHAN'S door Monday night in Venice, California, and instead of answering it, she called the cops. TMZ says when Linds asked what the man -- later identified as Lonny Short -- wanted, he would only say he needed to speak with her and refused to leave until she opened the door. The cops showed up and arrested Short for trespassing.

KHLOE KARDASHIAN NOT ALLOWED TO GET HER HAIR DID: Despite being 27 years old, KHLOE KARDASHIAN is not allowed to change the color of her hair without permission.

Radar Online says Khloe wants to go blonde, but E! and her mom won't let her. Their "source" says, quote, "Executives at E! want Khloe to remain a brunette so that it doesn't date the series when it re-runs. [They] want all of the sisters to have a similar look because the girls are branded as sisters and having one of them showing up on screen with hair a different color, throws that off, and they don't want to alienate viewers."

If you want to see Khloe with blonde hair, here's an old picture ...

RELATIONSHIP REPORT: By all accounts, DEREK JETER and MINKA KELLY look to be back together. The couple, who announced their split five months ago, spent the holiday weekend in Paris. An eyewitness tells People magazine, "They looked much in love. They were always very, very close [and] very playful as a couple with each other."

2. ALEX RODRIGUEZ may be taking a page out of GEORGE CLOONEY'S and hooking up with a former WWE diva. Sources say he's been hanging out with STACY KEIBLER'S buddy TORRIE WILSON.

3. Rumored couple OLIVIA WILDE and SNL star JASON SUDEIKIS stepped out together last week at a Kansas University basketball game. The pair was photographed sporting the home team’s gear and clapping and cheering.

HOLIDAY ENGAGEMENTS: MATTHEW MCCONAUGHEY and CAMILA ALVES have ruined their perfectly good relationship by getting engaged over Christmas. They have a 3-year-old son named Levi and a 2-year-old daughter named Vida

2. STEVEN TYLER also got engaged over Christmas. He slipped a five-carat rock on his longtime girlfriend Erin Brady's finger. And why wouldn't she say yes to THIS? ...