It wasn't too long ago when a shot of Mary-Kate Olsen smiling was as elusive as Bigfoot strolling in the woods, but in recent weeks, she's repeatedly been caught on camera flashing her pearly whites. A good sign, right?

Depends who you ask.

Dueling reports on MK's well-being emerged this week, with one declaring her happier than she's ever been, and the other predicting a return trip to rehab.

Let's start with cheerier stuff first, courtesy of FoxNews.com, which says Ashley's more hobo chic half has become best buddies with model Jessica Stam, who's been a "positive influence" on the previously issues-plagued starlet.

Mary-Kate, 22, was reportedly seen "happily" noshing at Stam's Fourth of July barbeque in the Hamptons, with the two later heading off to a nearby bash.

There, the lately in-the-pink-looking twin, who can currently be seen macking on Ben Kingsley in "The Wackness" and will soon guest-star on "Samantha Who?," was seen laughing and "happily" mingling with Stam and her pals, although she supposedly steered clear of any potential suitors and all cameras.

"I've never seen her in such good spirits, and she didn't look anything like her old emaciated self," relays a spy, who adds that she nixed alcohol and stuck with water (specifically, antioxidant water from Snapple, which -- product-placement alert -- sponsored the shindig, according to Fashion Week Daily).

Star, on the other hand, is convinced the mini-mogul has been spiraling since Heath Ledger's death in January (she was the first person called after he was discovered).

Among the evidence -- and we use that term more loosely than one of Olsen's trademark muumuus -- is her supposed "collapse" outside a Los Angeles club last month (video of the incident seems to show her tripping over her high heels while getting into her SUV amid a crush of paparazzi).

"Mary-Kate seriously needs to get to rehab, but she doesn't think she has a problem," a source tattles to the tab. "She thinks she's young, hip and entitled to live her life as she sees fit. But it's affecting everything."

In a sit-down with the July issue of Elle, Olsen tiptoed around her treatment in 2004 for a reported eating disorder, explaining, "Everybody is going to go through hard times. It's a part of life. I think the hardest part to get to is that point of asking for help or reaching out to other people and being honest with yourself."

She also talked about she handles being a celebrity in a shutterbug-filled world.

"It's very weird," acknowledged MK.. "I mean, if I see a paparazzi shot of me walking that's in a magazine or something at some event, it's as if I see it from an outsider's point of view. There's like a character, almost, and then there's me."

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