According to an eye-opening new Mashable report, their secret is actually a digital procedure of sorts called "beauty work," a technique which has managed to stay underground for more than a decade. The procedure involves a handful of skilled artists using highly specialized software in the final stages of post-production to "slim, de-age and enhance actors' faces and bodies."
"Nobody looks like what you see on TV and in the movies. Everybody is altered," says Claus Hansen, who works at Method Studios, a shop in Los Angeles that specializes in video retouching. "What they see is smoke and mirrors."
The technology is not only be used to enhance a star's appearance, but it can even be used as a type of "digital casting" when an actor or actress appears to be too old for a role.
When Lola Visual Effects shop in Hollywood aged Brad Pitt backwards for 2008's The Curious Case of Benjamin Button, making him appear as a twenty-something in a scene towards the end of the film, when in reality, Pitt was already in his 40s.
"We were seeing hundreds of thousands spent on this, anywhere from $500 to $2,500 per shot -- maybe more if there's a lot going into the scenes," a former top-level studio executive, who wishes to remain anonymous, tells Mashable. "It would benefit both parties. You want your actor or actress to do the publicity for the movie, so you wanted to keep them happy."
Not surprisingly, this type of beauty work takes time. A three-second medium to close-up shot can take anything from three to six hours, but the desired result can apparently be worth it. The report specifically mentions "a recent comedy hit [that] featured a top actress in her 40s" who required beauty work on every single shot she was in -- totaling about three months' work with artists working nonstop, seven days a week.
"Nearly everything written about the film remarked at how fit and young the actress looked," Mashable says. "No one suspected it was anything but good genes and clean livin'."
But if you think it's just Hollywood actresses getting beauty work, think again. The consensus is that men are getting as much work done as women.
Another anonymous beauty artist recalls "an A-list star in a superhero film" who was unhappy with his crow's feet in a close-up. The team ended up copying the crow's feet of a younger actor's face and transplanting it on the A-lister's face.
But why stop at one aspect of the body when you can get a whole new physique?
"We have taken actresses' faces and put them on more muscular bodies … that happens all the time," Hansen admits.
Though perhaps on the brighter side, there are some stars bucking the trend. Keira Knightly recently went topless in a photoshoot for Interview magazine to protest the overuse of Photoshop on her body.
"I've had my body manipulated so many different times for so many different reasons, whether it's paparazzi photographers or for film posters," Keira told the magazine. "That [shoot] was one of the ones where I said: 'OK, I'm fine doing the topless shot so long as you don't make them any bigger or retouch.' Because it does feel important to say it really doesn't matter what shape you are."
Check out Keira's headline-making photoshoot in the video below.