Michael Fassbender was nervous about playing Steve Jobs, noting that he looks nothing like the late Apple bigwig

Michael Fassbender isn’t afraid of a little friendly competition.

The actor, who is playing the legendary tech pioneer in the upcoming biopic appropriately titled Steve Jobs, knows how to ruffle some feathers when it comes to joking about another actor who has portrayed the late Apple bigwig.

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When asked at a New York City press conference how Fassbender, 38, prepared for his role as Jobs, he quipped. “I studied Ashton Kutcher.”

Kutcher previously donned the tech genius’ iconic glasses and black turtleneck in the 2013 biopic Jobs.

So if going up against a previous biopic didn’t intimate Fassbender, what did? Turns out, it was his lack of resemblance to Jobs that troubled the actor.

“Obviously I don’t look anything like Steve Jobs,” he said. “That was the first thing I said to [director] Danny [Boyle]. I said: ‘Christian Bale looks a lot more like Steve Jobs than me.’ ”

But Boyle wasn’t concerned with outer appearances; he was confident that Fassbender’s acting would make up for the lack of resemblance.

“He wasn’t interested in that – he wanted to get the energy and essence of the man and go with that,” Boyle said.

And it seems Boyle was right. Steve Jobs is already receiving award-season buzz, and Fassbender’s costar Kate Winslet can’t stop gushing about how great the actor was, either.

“He’s an extraordinary actor and I’ve never seen such professional behavior by an actor, he was just amazing,” Winslet, 40, told PEOPLE at the New York Film Festival premiere of the film. “He set the bar really very high for all of us. We were so lucky to have him.”

Winslet plays Jobs’ confidante and one of the few people to work with him throughout his career, Joanna Hoffman. And while Jobs and Hoffman had a tight friendship in the film, Winslet admits that she formed a special bond with Fassbender off set.

“We were quite close, actually,” she said. “We were very, very close, and we had a great time working together.”

In order to prepare for the film, many cast members – including Winslet and Seth Rogen, who plays Apple cofounder Steve Wozniak – were able to meet with their characters’ real-life counterparts while researching their roles.

When Rogen heard that Wozniak was a fan of the film, the actor was pleasantly surprised – and a bit relieved.

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“It was very nice,” Rogen, 33, told PEOPLE of hearing of Wozniak’s praise. “Honestly, it wasn’t something I thought a lot about, and then when I heard he liked it, I was like, ‘Oh man, he could have hated it, I should have put more thought into that going into this thing.’ But it was great.”

He added with a laugh, “I’m the glad the guy who invented the computer doesn’t hate me!”