Lady Gaga got the best seat in the house for opening night at L.A. nightspot Trousdale. The pop star, in a short blonde wig and black hat, played musical chairs once she got to her table, whispering in her friends' ears and moving around her booth. Gaga was in a pleasant mood, but got really excited and started dancing when the deejay played her hit "Paparazzi." Meanwhile, Hayden Panettiere worked the room, chatting at friends' tables when she wasn't hitting the dance floor with a girlfriend.

• Miley Cyrus, vintage shopping at the What Comes Around Goes Around boutique in L.A. with her puppy, Mate, and a girlfriend. Shoppers were especially attentive to her pooch, but Cyrus was focused on the clothes. She tried on various items, and left with some boyfriend jeans, cut-off denim shorts and vintage T-shirts.

• Justin Timberlake was sampling his own 901 Silver Tequila during a night out at Lavo in Las Vegas. The singer-actor also danced to tunes spun by DJ Crooked, and was spotted dining at Tao earlier with friends and business associates.

• It's a Today show reunion – but was it also a business meeting? Matt Lauer and former co-anchor Katie Couric, lunching at Le Caprice inside New York's Pierre Hotel along with Andrew Lack, CEO of Bloomberg LP.

• Catherine Zeta-Jones, dining in an alcove at Rouge Tomate in New York with husband Michael Douglas and two friends. The group stayed for two hours, chatting about the Oscars, among other things, and drinking red wine.

Lady Gaga: Why I Passed Out Three Times

Days after crumpling to the floor during a New Zealand concert, Lady Gaga explained her alarming performance.

"I was so jet lagged," she told the Australian radio show Kyle and Jackie O on Friday. "I passed out about three times on stage that night but I got myself to the floor. I'd rather die on stage than walk off because I was going to pass out."

This isn't the first time that Gaga's whirlwind rise to superstardom has taken its toll. Back in January, she was forced to cancel several shows, citing exhaustion.

PHOTOS: Lady Gaga's 25 Wackiest Looks

One source fears that the pop star is suffering from the stress of her staggering fame. "She's on the verge of tipping," says the source. "She's only human."

Still, the singer insisted on the radio show that she's feeling "completely rejuvenated and excited."

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