Though taking on the role of iconic Apple co-founder Steve Jobs is predictably emotionally draining, it turns out the highly coveted role is also physically demanding -- just ask Ashton Kutcher, who seriously injured his back while mimicking Jobs' specific walk.
"I saw this weird documentary that was done ... when Steve was building NeXT. And there was some really great footage of him walking through the field, and I noticed this kind of bizarre walk that he had," Kutcher explains to ET's Nancy O'Dell, who talked to both Kutcher and Josh Gad (who plays Apple co-founder Steve Wozniak) ahead of Jobs' big release. "So I just started trying to emulate it. I learned that he went on hikes a lot when he took meetings, and he would go and walk with people around, so, I would take my meetings during the day while going on walks and try to walk like that. At first, it was like five minutes and then I would forget, and then it was 10, you just kind of practice."
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"It kind of messed up my back a little bit. You know, changing your walk changes your entire biophysical structure. ... And I threw by back out, and I had to have a chiropractor come and sort me back out because I actually changed my physical ... I'm sure I changed the way I actually walk a little bit."
As for technology today and Kutcher's heavy presence on Twitter, he admits that he's made plenty of mistakes but one particular one stands out -- his infamous tweet about the late Penn State coach Joe Paterno, which he ended up publicly apologizing for.
"Listen, I've had plenty of gaffes, and I think it's one of the things that makes you just kind of want to jump in a hole and hide. It really is," he says, before attributing his ignorance of the situation to "17 hour-a-day" work days at the time. " ... You wouldn't have all these celebrities quitting Twitter all the time if it wasn't like this blastful feedback loop where people have absolutely no tolerance for inaccuracy, or people being incorrect, unless it's in an effort to take somebody down. You know, it is what it is, and I think you just have to be more careful about what you say. Instead of being in a world where we edit later, we need to edit first."
Video: What Made 'Jobs' Great?
Check out the video to hear what Kutcher found particularly daunting about playing Jobs, and The Book of Mormon star Gad's response to Wozniak reportedly not liking the way he's portrayed in the film.
Jobs hits theaters August 16.