Just how hands-on is Drew Barrymore as a producer? E! Online's Marc Malkin reports the sunny star was spied in Las Vegas on Sunday night getting up close and personal with Justin "I'm a Mac" Long, one of the many actors populating the cast of the forthcoming romcom, "He's Just Not That Into You," which Drew is co-producing (she also co-stars). The oddball duo -- with Barrymore's BFF Cameron Diaz in tow -- hung out together at hot spot Jet, where an eyewitness claims they were "making out" in the VIP area. Days earlier, paparazzi caught a camera-shy Drew, 32, and Justin, 29, exiting the Chateau Marmont in Los Angeles and driving off together. The actress was most recently linked to filmmaker Spike Jonze, whom she was first seen snuggling up to in February. They were snapped out and about together in Los Angeles just two weeks ago.

Is John Mayer trying to get the media to back off his rumored romance with Diaz by downplaying its seriousness, or is he just making sure his supply of hot-and-cold-running babes doesn't dry up due to premature reports he's taken? Sources blab to the New York Post that, even though the lately comely crooner has been repeatedly spied enjoying the company of the long-legged actress, he's still on the prowl. According to one insider, Mayer and Diaz are "definitely not exclusive ... He takes non-famous girls to dinner at low-key restaurants all the time. He doesn't like having the paparazzi all over him." Pipes in another mole, "[Mayer's ex] Jessica Simpson used to call photographers and set him up all the time. He tries to shy away from it. John and Cam aren't official ... he's still on the market."

That could be good news for Simpson, at least according to Us Weekly, which claims the top-heavy blonde is "really jealous" of her former beau's quality time with Diaz. "She had her mouth open a mile wide when she found out," maintains a spy. "She just freaked." Jessica "thinks about him all the time" and "is so not over him," adds the source. Still, that didn't stop her from hitting Los Angeles hot spot Hyde a few days back with a mystery man. E! Online believes the "young, clean-cut guy" who kept his arm around Simpson all night may be a new suitor.

With Shia LaBeouf's star climbing faster than Lindsay Lohan's rehab bill, you'd think any starlet would be thrilled to be romantically linked to him. But Rihanna, whose ubiquitous chart-topper "Umbrella" has burrowed into many a brain in recent months, denies rumors that she's hot and heavy with the appealing actor. Although the two were recently photographed hanging out together, she insists to "The Insider," "Me and Shia, we are just friends, you know. We barely even know each other."

Zac Efron and Vanessa Hudgens apparently aren't yet famous enough to be showered in designer swag. The New York Daily News says the non-threatening flames stopped into Neiman Marcus' Chicago outpost a few weeks back while promoting "High School Musical 2" to do a little shopping. Generous boyfriend that he is, the unflatteringly swoopy-banged actor treated his apple-cheeked galpal to a pair of $1,200 Rene Caovilla stilettos, which were reportedly returned -- scuffed soles and all -- the next day. "These shoes weren't gently worn. They were all torn up like she was dancing all night," a spy tells the paper. "Department stores call those people 'the renters,' who return the stuff the next day. It's unusual to do it with shoes, though."

Tom Brady just welcomed a son with ex-girlfriend Bridget Moynahan, but he's still making time for blatant shows of schmoopiness with girlfriend Gisele Bundchen. People reports the square-jawed Patriots quarterback and the Brazilian bombshell put on a very public display of affection during a recent day out in Boston as they stopped on the sidewalk to lock lips.

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