Jim Sturgess has been busy of late. After taking a lead role in Julie Taymor’s Beatles musical “Across the Universe,” he went on to a supporting part in “The Other Boleyn Girl,” and now stars in “21,” playing an MIT student who becomes part of a team put together by an unscrupulous math professor to win big at blackjack in Las Vegas by following his system of counting cards. During a recent stop in Dallas he discussed his suddenly booming career.

“I’d been doing a lot of music at that point,” Sturgess said of auditioning for Taymor’s film, “so the acting had taken a bit of a back seat because I was focused on being in a band. That was taking up all my time. So when ‘Across the Universe’ came, it was just a dream. All the things that I love—drawing, painting, singing, acting, music and The Beatles in the sixties! It couldn’t have come at a better time.

“I learned that they were doing auditions for a Beatles musical, which I didn’t think was a very good idea at the time. But I went along anyway, thank God. It was to my benefit that I had that attitude, I think. Because I didn’t care for it very much, I wasn’t particularly nervous. I just kind of went in and sang a few songs on my guitar. I didn’t even know Julie Taymor was directing.”

For “21,” Sturgess recalled, “I was asked to put myself on tape, read a few things from the script. I just did a kind of botch, a camcorder thing, and didn’t think too much of it. I was filming ‘The Other Boleyn Girl’ at the time, so I was stuck out in rural England, trying to find anyone with a camcorder. I did an American accent in that, as good as I could at that point. So I guess [director Robert Luketic] believed I could pull it off with a bit of work.”

And work it was. “Doing the American accent was a big challenge for me,” Sturgess admitted. “But it definitely helped, having everybody else around me that was American. You kind of latch onto the sounds you’re hearing around you, and just kind of hope for the best, you know? But it’s really hard to train your mind and your mouth to speak in a completely different way.” When asked whether there were any words that gave him particular trouble, he smiled and said, “Yeah, ‘dollars’ and ‘cards,’ which are the two words I had to say all the time.”

Among Sturgess’ co-stars in “21” are Kevin Spacey, as the teacher who sets up the scheme, and Laurence Fishburne, as the casino security man who at one point does some arm-twisting on Sturgess’ character. Spacey had taken over directorship of the venerable Old Vic company, he recalled, and “he invited me to his play when he found out that I’d gotten the part. He phoned me up and I met him and we had lunch, and then I went to see his play. That was the first time I’d seen him. He’s an amazing actor, an amazing guy. Anytime you work with someone who’s really good at what they do, it helps you.”

As for Fishburne, Sturgess remembered the day on which they shot the scene in which the security man ties him to a chair and roughs him up. “He intimidated me as much off camera as he did on camera on that particular day,” he said. “I love all that stuff, when you really get into it and you’re really playing hard. It’s a tense scene, and then and then at the end we gave each other a man-hug.”

Sturgess said that it was a help to have Jeff Ma, on whom his character was based, on set. “I’ve never played cards,” he said, “so it was a new thing for me, like blackjack camp, and it was good having him there.”

Ma, who traveled to Dallas with Sturgess, praised him enthusiastically. “He did great,” Ma said. “He’s an awesome actor, and I love what he did with the role. I saw myself in a lot of what he did. He really wanted to spend time with me and ask me questions. And his speech coach made me sit with him and say certain words, and he’d mimic me.”

Ma admitted that the narrative of “21” differed substantially from his actual experience. “The storyline behind the movie changed quite a bit from what happened in real life,” he said. “But it’s not autobiography. My life is really not interesting enough to condense into a two-hour movie and have lots of people see it, which needs to happen for it to be successful. The movie [adds] elements that make it more entertaining and easier to work as a two-hour movie.

“But there are lots of parts that are dead-on.”