Three of the young stars of “Step Up,” the new drama-with-dance co-written by Duane Adler (“Save the Last Dance”), visited Dallas recently to promote the picture, in which Channing Tatum (“She’s the Man”) stars as a street-wise Baltimore kid who becomes the unlikely performance (and romantic) partner of talented ballerina Jenna Dewan (“Tamara”) after he’s assigned to do community service at the arts-magnet high school he vandalized and she attends. Drew Sidora, the third visitor, plays Jenna’s best friend, a talented dancer herself.

All three had special praise for Anne Fletcher, a well-known choreographer who makes her directing debut with the film. Dewan said, “She had a vision of how she wanted things. A ‘realistic love story with a seasoning of dance,’ is how she put it. She wanted the dance to supplement the love story.” And Tatum recalled Fletcher saying, “I don’t want this to be an hour-and-a-half music video. I want it to be a story that has dancing in it, that’s accented by dancing, not totally about dancing.”

That’s why it was important for the stars to be able to act as well as dance. For Dewan and Sidora, who were trained dancers as well as actors, the combination wasn’t too daunting, but Tatum admitted it was a challenge for him. “I’ve never taken a dance class,” he said. “But I have a lot of friends that just love dancing, and growing up in Florida, there are things called quinceaneras, and we had one of those every weekend in Florida because there’s such a huge Spanish population. So the moms would always grab the white guys and take them out on the dance floor. And so I was just dragged out there, and it was the joke for so long that eventually I said, screw this–I’m going to learn how to dance just so I can’t be made fun of forever. Then once I realized that dancing was fun and that all the girls were dancing, I knew I was going to be good at it, because it was going to come in handy later on.”

Still, being self-taught put Tatum at a disadvantage. “I did an acting audition first, and then a dance audition,” he recalled. “And that was pretty nerve-wracking. I’m used to free-styling–that’s just easy, you can do whatever you do, whatever you’re good at.” He was so concerned that while he was in Vancouver shooting “She’s the Man,” he went to a dance studio. “I took a beginner’s class with these little girls around me,” he said. “These girls were killing it, and I looked like the biggest giant goof in there. It was pretty embarrassing.”

In retrospect, though, Tatum believes that his relative inexperience was right for the story. “I was Tyler,” he said. “I was supposed to be a really good, raw street dancer. I wasn’t supposed to know how to do any of the technical stuff, and I was supposed to look awkward.”

“Step Up” was shot entirely in Baltimore–Sidora explained, “It was important for the director to get the environment–Baltimore is one of a kind, and you can’t really create that”–and the four-month shoot included four weeks of preliminary rehearsals, mostly on big dance number that closes the film. “We hung out a lot, kind of like family,” Sidora said. “We were out there a month before shooting, and we were all kind of new–it was our first leading roles. So we were just all no egos, and asking each other for advice. We really leaned on each other.”

Dewan added, “We had four weeks, about a month, of rehearsals, every day ten hours. I’ve done dance rehearsals like that before, but this was just myself and Channing, so it was a little bit more intense. But it was fun–a lot of fun. If you could see our out-take reel, you’d be crying. Channing is hysterical, and he’s always making me laugh. We goofed off and laughed and worked really hard, all at once. Channing, he’s very spontaneous. I learned a lot from him.”

Tatum recalled being more nervous. Comparing the dancing in this picture to the on-field soccer action he did in “She’s the Man,” he readily said that the dancing was more challenging. “The soccer was frustrating at times,” he said, “but it was less intricate as long as you knew what direction to go. I could do the flips and stuff–it’s kind of what I’m good at–so that was easy for me, as far as doing the tricks. Controlling the ball, and looking like you’d done it forever, that was kind of hard. But the dancing was so much more intricate. The details are what make the dance more interesting. A facial expression, those little tiny things for emphasis, make something good amazing.”

And mastering an elaborate routine was daunting. “I was shaking terrified,” Tatum said of the month-long rehearsal. “They called me Full-Out Freddy, because I didn’t know how to mark anything. I didn’t remember the steps unless I did it flat-out. We did it for three and a half weeks, and I had it down. Then we started shooting, and I just forgot about the dance. I wasn’t focusing on it. And then it came time to shoot it. The day before, we had a rehearsal with everyone, and I had forgotten all of it. I was freaking out–it was a nightmare. But we got it done, somehow.”

The dance routines took a physical toll, too. Sidowa recalled that the finale, which took five days to shoot, was hard on the legs. “We had to wrap our knees up,” she said. “They’d swell up from just getting on the floor so many times.” And Dewan was injured during a routine with Tatum. “Channing’s fault–he caught me and hurt my rib!” she said, laughing. “Actually, we were doing a lift and I came down wrong, and he caught me. I’d already injured a rib before and I kind of re-injured it. But it didn’t fracture, just a bad bruise. For a week, a week and a half, I couldn’t dance or lift my arm very well. It was pretty painful.”

Tatum remembered a different kind of injury–to the psyche. In one scene of the movie, he does some moves at a ballet bar while a little girl in front of him (the daughter of an assistant director, actually) shushes him for not being serious. “I was not supposed to laugh in that scene, not at all, but I could not not laugh,” he said. “I was there in tights, which I’d never worn before in my life. And that was not embarrassing at all!”