Rupert Friend of "Homeland" on the Value of Experience Kent Smith/Showtime Rupert Friend, right, with Mandy Patinkin and Claire Danes on "Homeland," in which he plays Peter Quinn, an enigmatic agent. Ms. Danes says Mr. Friend has a "truly creative, curious, adventurous spirit." Early on in the third season of "Homeland" - which begins on Showtime on Sunday - the actor Rupert Friend, as the enigmatic black-ops agent Peter Quinn, hunches, shirtless, over a homemade explosive device. There is a stillness to Mr. Friend's performance, a noiseless stoicism that only amplifies his character's inscrutability: whatever Quinn is up to with that bomb (and in that moment, it's fruitless to even guess), it seems extraordinarily unlikely that he'll miss his target. Off-screen, Mr. Friend, 31, is relaxed and puckish. At breakfast on the Lower East Side, he eschewed a menu to order extemporaneously, chatted with the waitress in her native Italian, and gallantly selected an entree for his dining companion. "She'll have the frittata," he announced, grinning. Unlike Quinn, Mr. Friend is interested in cultural ephemera, especially books - he had recently finished John Steinbeck's "East of Eden" and was ferrying Christopher Hitchens's "God Is Not Great" in his tote bag - but the two share a penchant for discretion and humility. "I am quite British about all that," Mr. Friend admitted. When you're pleased with what you've just done, that's when it's unbearable. In the previous seasons, viewers have witnessed Quinn in situations that might cripple ordinary civilians (if not physically, then emotionally). "Eating cold tuna fish out of a tin on a porch while two people are in love across a lake - I think that's desperately lonely," Mr. Friend said of one pivotal scene. But at the start of the third season, Quinn is beginning to deal with the psychological ramifications of his job: the tension between his training and his empathy, his patriotism and his self-preservation. The first two episodes have Quinn scrambling to reclaim his humanity before it's lost. Alex Gansa, a creator and an executive producer of "Homeland," suggested in a phone interview that one of the primary themes of the new season was "the cost of being an intelligence officer." He believes there's an addictive quality to the work. "The adrenaline, the quarry, the chase - it's powerful stuff," he said. He also acknowledged that Quinn was due for some kind of reckoning: "When is he going to realize what the lifestyle has cost him, in terms of his own family and his relationships to other human beings?" Mr. Gansa asked. Mr. Friend acknowledged the shift in his character and what was at stake. "I think that Quinn is potentially recognizing that as a very real possibility, and trying to head it off, trying to save himself from that fate," he said. He doesn't want to end up a servant of the machine, some kind of automaton who, you know, pulls the trigger until the trigger's pulled on him. In Mr. Friend's view, his character "is meticulously trained and doesn't need anything but the essentials." The actor would later send an e-mail to this reporter with a Frank Lloyd Wright quote he deemed germane to Quinn's abstemious ethos: "The elimination of the insignificant." Beyond "Homeland," he is still best known for his roles in the historical dramas "Pride and Prejudice" (starring Keira Knightley, whom he dated from 2005 to 2010) and "The Young Victoria." A native of Stonesfield, Oxfordshire, who trained in London, he made his film debut in 2005 in "The Libertine," playing a friend and lover to Johnny Depp's John Wilmot, the second Earl of Rochester. In his latest feature, "Starred Up," which played at the Toronto International Film Festival, Mr. Friend portrays a soft-spoken prison therapist. In an e-mail interview, the film's director, David Mackenzie, echoed critics when he called the performance "brave, edgy and sometimes very vulnerable." He said he cast Mr. Friend in part because of his work on "Homeland." Mr. Gansa said Mr. Friend brought "a very specific, laconic intensity to the role." He added: "A lot is said with quiet. That's a gift. It's hard to find. His "Homeland" co-star Claire Danes, in an e-mail from Charlotte, N.C., where the show is filmed, wrote that "Rupert is playful and boyish on set, but incredibly focused, present and generous when we get into a scene," adding: "He's a bit of a nonconformist - he will ride his motorcycle to work in the pouring rain - but it's never for show. He's got a truly creative, curious, adventurous spirit. Forking a plate of scrambled eggs and salad, Mr. Friend admitted to a bold streak, to favoring experience over observation.