Jennifer Lopez was barely recognizable in her grey sweats Saturday as she took daughter Emme to an after-school activity before hitting up her own activity -- sweating it out at the gym with boyfriend Casper Smart!

J Lo even changed into a different sweatsuit half way through the day -- but hey, she's probably got a closet full of them.

The singer didn't look quite as glamorous as she does in her chic American Idol wardrobe ... but hey, she's still Jenny From the Block on the weekends!

Heidi Klum was ready for action Saturday in her Brad Pitt-style jumpsuit!



The supermodel mom picked up son Henry at karate and took him to the park with daughter Lou. Klum braved the slide with Lou and helped her out on the swings.

But we have to ask ... what's with this new mechanic-chic style???

Brad Pitt and George Clooney participated in a table reading of the play 8 last night -- a work that explores the legal battle to overturn Proposition 8, California's ban on gay marriage.

Clooney recently addressed rumors he is gay, in an interview with The Advocate, saying: "My private life is private, and I'm very happy in it. Who does it hurt if someone thinks I'm gay? I'll be long dead and there will still be people who say I was gay. I don't give a s--t. I think it's funny, but the last thing you'll ever see me do is jump up and down, saying, 'These are lies!' That would be unfair and unkind to my good friends in the gay community. I'm not going to let anyone make it seem like being gay is a bad thing."

Pitt has said he and partner Angelina Jolie wouldn't marry until ALL couples have the legal right to wed. Pitt and Clooney were joined by fellow actors martin Sheen, Jamie Lee Curtis, Kevin Bacon, Modern Family's Jesse Tyler Ferguson, Glee's Jane Lynch, Matthew Morrison, and Chris Colfer, and George Takei.

Click through to about the 30-minute mark to see a recording of the table reading at the Wilshire Ebell Theater last night ...

It's an interesting twist on Bravo's Real Housewives series ... Lindsay Lohan plays Rapunzel, with the rest of the cast filling in as other Disney "princesses" -- Belle, Jasmine, Snow White and Cinderella.

Check it out -- Lindsay rocks!

Angelina Jolie took Shiloh, Vivienne and Knox to see The Secret World of Arrietty at Disney's El Capitan theater Saturday in LA.

Daughter Vivienne got all dolled up for the event, putting on mom's red lipstick and a black and white silk dress!

Meanwhile, Shiloh sported her usual t-shirt and pants as she clung to her licorice and popcorn bucket when the group left the theater.

Like mother, like daughter! Well, at least one daughter!

Katy Perry looked was walking art as she arrived to the Viktor & Rolf Fall/Winter 2012 show in Paris Saturday.

Definitely in a blue period, the singer was styled to the nines ... And check out her purse -- it's 500 mg of something!

Brad Pitt, Angelina Jolie and their brood LOOOOOVE McDonald's!

We've caught various members of the Jolie-Pitt family visiting McDonald's and other fast food restaurants at least four times in the past three weeks and Saturday was no exception ... they piled in their SUV and hit-up the drive-thru!

Brad recently admitted he gives his kids Coca-Cola sometimes for breakfast, when he needs to get them up and out the door early.

And we've seen the famous parents feeding their kids Cheetos and other junky snacks quite often. So what gives? Why is Hollywood's hottest parental unit not so concerned with their children's diet?

Oprah Winfrey has snagged the interview everyone must have been vying for ... Sorry Matt Lauer! Sorry Kelly Ripa! ... The Queen of Daytime will sit down with Whitney Houston's 18-year-old daughter Bobbi Kristina for a March 11 chat on Oprah's Next Chapter on her network OWN.

The one-hour special will also include interviews with the late singer's sister-in-law/manager Patricia Houston and her brother, Gary Houston.

There has been much speculation about Bobbi Kristina's health since her mother's passing, particularly after she was hospitalized twice in the days following Houston's February 11 death. Then, Bobbi Kristina went missing in the hours after her mother's funeral but was later said, by a family member, to have been spending time alone to collect her thoughts.

Various reports claim the teen is haunted by the same addictions that led to Whitney's declining health -- some reports have even asserted that Houston did drugs with her daughter at times.

We bet Oprah will ask ALL the questions we all want to hear the answers to ... we'll tune in March 11th!