Matthew McConaughey Wears a Stetson and a Smile on the Set of ‘The Dallas Buyers Club’ (PHOTOS)

Even as Matthew McConaughey continues to lose weight for his role in The Dallas Buyers Club, he’s always wearing that trademark smile — along with his cowboy hat and boots.

The Hollywood hunk, who shocked the world with his dramatically thin frame since losing nearly 40 pounds to play AIDS patient Ron Woodroof in the film, admitted to having “35 percent less energy” in a recent interview. But he’s not letting it get him down, as he’s hard at work — and taking photos with fans — on the New Orleans set, and Celebuzz has all the photos.

The 43-year-old told HitFix about how the drastic drop in weight is affecting his lifestyle:”I feel good now,” he admitted. “Overall, [I] probably got 35 percent less energy. But the tough part is there have been plateaus. Getting past 170 was really hard, but then once you get 167, the next seven come off easy. Getting past 160, really hard, but then you fly down to 150. Getting past 150 was really hard and then, bam!”

Celebuzz recently spoke with nutritionist Lisa De Fazio who explained how this type of rapid weight loss could be dangerous if not monitored appropriately.

“The harmful consequences of this type of rapid starvation weight loss are muscle wasting, hair loss, anemia, strain on the heart and other organs, dehydration and possible heart attack,” she explained. “In my opinion he looks too thin for his height and appears unhealthy. I know it is for a movie, however, I hope his medical team are monitoring him closely.”

But McConaughey isn’t the only one transforming his movie star good looks for the sake of the film’s authenticity.

30 Second to Mars frontman Jared Leto has also been slimming down for his role in the feature film as a cross-dressing, transsexual woman with HIV during the height of the AIDS epidemic in 1986.

“Your body goes through weird stages,” the 40-year-old star previously told Vulture.

Click through the gallery above to see how aged McConaughey looks. How many years do you think he has added on? Let us know in the comments below.

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