Another Hollywood couple in a cheating scandal?

Reports surfaced this weekend that Liev Schreiber, 44, has cheated on longtime partner (and mother of his two sons), Naomi Watts, 43 -- and that it happened the same weekend Ashton Kutcher allegedly cheated on Demi Moore.

Was something in the water??

According to TheDirty.com, Liev had been filming Mental in Australia (where Naomi Watts is from.) In the film, a swimwear model named Phoebe Roberts (left, in Kulu Swimwear) served as body double for Liev's co-star, Toni Collette.

Schreiber and Roberts supposedly hooked up after the movie's wrap party on Sept. 24. The actor allegedly took Roberts back to his apartment.

Liev's rep has denied the allegations, saying, "This is a complete fabrication."

Schreiber and Watts have been a couple since 2005. We spotted them out together as recently as Sept. 27 in NYC -- only a few days after the alleged hook-up with Roberts. See the pic after the jump.

We spotted Rob Kardashian as he left gourmet supermarket Bristol Farms in Beverly Hills on Saturday.

While the reality star only grabbed a water, we're wondering if Dancing With The Stars is helping him lose weight like he'd hoped ...

Partner Cherly Burke has said that Rob has "lost a lot of weight." But what do you think -- does the 24-year-old look different?

Starkey Hearing Foundation

Miley Cyrus took her second mission trip to Haiti with the Starkey Hearing Foundation, where she lent a helping hand for hearing!

The singer distributed more than 400 hearing aids to people in need, and looked gorgeous as she posed for a photo with local children.

Nice work, Miley!

Pete Wentz stepped out to Starbucks with son Bronx in Beverly Hills over the weekend -- but of course, at almost 3-years-old (Bronx's b-day is in November), Bronx is too young for coffee.

So, he brought his own beverage! Looks like little Bronx (or should we say Batman?) wants to be just like Daddy! Too cute.

Rachel Zoe took a little rest from being a mommy as she shopped in Beverly Hills over the weekend.

After returning from Paris Fashion Week, the tired momma to baby Skyler, 7 months old, let hairstylist pal Joey Maalouf tote her baby boy around (see below.)

But, Rachel is a friend who returns a favor -- she sent Joey a gift! He Tweeted: "Thanks @rzrachelzoe for my #MAJ marc by marc duffel. Love your soul! Xo"

See another picture of adorable Skyler after the jump!

Kristin Cavallari and an equally stunning (and leggy!) gal pal were spotted shopping in Beverly Hills on Friday afternoon, and the ladies looked like they were loving the attention from photographers.

We're not sure what KC bought, but it seemed to help take her mind off of last week's Dancing with the Stars elimination...

This may be a new couple alert, but it's also a bit of an odd couple alert!

We haven't seen Serena Williams on the dating scene since she split from rapper Common in 2010, but last night the tennis superstar went out with country
singer Jake Owen! The duo dined to Matsuhisa in Beverly Hills, and they seemed just as surprised as we were when they left the sushi restaurant. Serena tweeted, "@jakeowen had so much fun tonite! Yea can't wait to see concert tomm! Fun time see u tomm/today!!!"

A photographer on the scene tells X17online exclusively that Serena and Jake didn't make much of an effort to sneak out separately, but they tried to keep their exit "as low key as possible." Hmm, so are they just friends or something more?

What more do you need?!

Paris Hilton dined at the hip new Italian eatery Mercato di Vetro with her brother Barron and several other pals last night, and she looked absolutely stunning in a sexy Herve Leger dress. Paris' night didn't end there, but it sounds like she got home as a reasonable hour, as she was off to a photo shoot early this morning. Can't wait to hear more about that ... maybe she'll tweet us a pic later?