Chiwetel Ejiofor has appeared in several films since Stephen Spielberg chose him for a small role in “Amistad” when he was a 19-year old drama student, but Chewy, as he’s known to his friends, has made his mark most prominently on the stage. It was his appearance in the London National Theatre’s production of “Blue/Orange,” in fact, that led to his starring role, along with Audrey Tautou and Sergi Lopez, in Stephen Frears’ drama “Dirty Pretty Things,” in which he plays an illegal Nigerian immigrant who chances upon nefarious doings at the London hotel where he works as a night clerk while beginning a halting romance with the Turkish girl with whom he shares a flat.

As Ejiofor explained during a recent Dallas interview, Frears saw him in the play, and suggested that he tape a few scenes from the script to serve as a preliminary screen test. “[The fact that] he was going to make it…was a great incentive to me, because I’m a great fan of his films,” he explained. “But actually, even independently of that, I think I still would have wanted to make the film. I just thought the script was terrific….I was very eager to play the part.”

So Ejiofor took Frears up on the offer. “A friend of mine was making a music video, so I got in contact with him….We did three scenes from the film with other people, and sent it to Stephen. You know,” he added laughing, “he didn’t like the direction–as he later pointed out–but he did think that it warranted a second, more formal screen text. So I did that.” And the part was his, even though the production company briefly argued that a name star might be preferable.

What attracted Ejiofor to the project, in addition to Frears’ involvement, was the complexity of the screenplay and the opportunities it offered to him in particular as Okwe, an erstwhile physician working menial jobs under the radar to escape the notice of immigration authorities in England while making ends meet, whose medical expertise eventually draws him into a sinister black-market scheme. “It’s engaging on a number of levels, and at the same time has a wider idea of social realism,” he said of the film. “It wasn’t classed simply as documentary filmmaking…just based on social realism. I think [Stephen] was eager to make sure that people had a good time in the two hours–that they watched something…that had very firm elements of being a thriller and then also have some light touches, dark humor, and then this blossoming, touching, emotional love story [between Okwe and Senay, the Turkish girl played by Tautou] at the center of it.”

His role was similarly complex. “[The story is] such a sequence of duets, in a way, in that the character goes to archetypal people, really–a lover or a friend or an enemy or a work colleague–and it’s all kind of little moments, pockets, which was a gift to me, because it allowed me to play a broad range of very subtle differences in relationships,” Ejiofor said. He was particularly anxious that Okwe, though a heroic figure, should not seem a simple one. “I didn’t want him to be sort of insanely benevolent, just this saintly figure,” he explained. “I wanted to make sure that his benevolence came from a desire to control the situation, to contain himself–by doing things in a right and moral way, it was actually a way of hiding from any kind of emotional connection with the world, sort of sterilizing himself.”

Ejiofor didn’t realize the enormous contribution the crew were making to “Dirty Pretty Things” until he saw the finished film at the Venice Film Festival, where it received a prolonged ovation. “I’d always felt that the story held so much, and the characters,” he recalled. “But when I saw it, what I didn’t know or account for, was the work that had gone into what Chris [Menges] was doing–the cinematographer–the work he was doing with Stephen and Hugo [Luczyc-Wyhowski], the designer, to encapsulate this world. That’s one of the things I found most incredible, that they were able to create this environment that was heightened, but wasn’t unfamiliar…I didn’t know until I watched the film how terrifying a hotel lobby at night can be.”

Ejiofor enjoys making films–particularly this one–but plans on returning to the theatre as well: “I’ll definitely go back to the stage. I had a great time doing this film, and I’d love to do more films, but I don’t think it’s possible for me not to be involved in the theatre.” Both media, he opined, have advantages and disadvantages for an actor. Live performance, he explained, has the virtues of excitement and immediacy. Yet it also has its drawbacks. “There’s something very frustrating about being a stage actor,” he said. “Even if…you feel you’re close to getting a character right on stage one night, the next night it’s completely gone. There’s no way of containing it. Of course in cinema you can contain it, and if you feel you’ve done a good take, it’s there. And if you feel you haven’t, you can have another go at it. But at the same time you give away your performance to other people and other factors. There are things about both mediums that are challenging, and there are things about both mediums that are very exciting. I would hope to continue to do both, for as long as I can.”