Tuesday

Caught in the Act!

09/01/2009 at 06:00 AM EDT

• 90210's AnnaLynne McCord got a splash of surprise while hosting the MGM Grand's Wet Republic pool party in Las Vegas: the unexpected arrival of Twilight hottie Kellan Lutz. The two, who have been linked for months, escaped prying eyes behind the curtains in their VIP cabana. When he left, Lutz sported a baseball cap and tried to sneak away inconspicuously. Meanwhile, McCord spent time at the pool with her sister, Angel, and the two checked out Cirque du Soleil's Mystère at the Treasure Island Hotel later that night.

• Rihanna, partying with rapper Aubrey "Drake" Graham – he's denied reports they are romantically involved – and good pal Katy Perry at h.wood in Los Angeles. "[Rihanna and Drake] sat at a private table, just talking, but they looked very cozy with each other," a source tells us. Perry arrived with Rihanna earlier in the evening, but they later moved to the private Belltower Room where Perry was presented with a cake that she "was eating and putting all over her face," according to the source.

• Matt Damon, causing a stir at Santa Monica's Café Delfini. The actor was eating with wife Luciana, as many excited diners looked on – but never approached the actor.

• Chris Pine, celebrating his 29th birthday recently with friends at Boa Steakhouse in West Hollywood. The Star Trek actor hung out on the patio, where he enjoyed wine and some of the restaurant's staples, including Wagu beef and S'mores, presented to Pine as a special birthday dessert.

• Kelly Osbourne, catching the Liza Minnelli concert with a group of friends at L.A.'s Hollywood Bowl. An observer tell us that the newly minted Dancing with the Stars contestant, who was spotted texting madly before the show, looked "totally cute" dressed down in jeans.

• By DAVID CAPLAN, ALEXIS CHIU, MARK GRAY, EUNICE OH and SUSAN YARA

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