When you picture John Abraham, you think of broad shoulders, chiselled six-pack abs, and an air of calm. But for Tehran, the brief was different. This was about embodying a covert agent — moving, reacting, and sustaining that persona for over a year of filming in 2024.

For Vinod Channa, Abraham’s long-time trainer, this required a tactical shift. “John’s fitness in Tehran had to match the way a covert operative would train,” he says. “It’s not about bulking up. It’s about agility, speed, endurance, and being able to perform again and again during long shooting days.”

Channa devised what he calls “spy fitness” — a mix of cardio, weights, self-defence drills, and agility work. “A spy’s job involves running, jumping, fighting; it’s not just one skill. So we mixed everything from the training level itself,” he explains. The varied regime prevented overuse injuries and kept every muscle group active. Diet was equally precise. “Preparing one star and one character means putting in excess effort at the start. You have to build the body, then maintains the energy for action scenes that go on for 12 to 14 hours of shooting.” Calorie intake was fine-tuned: carbs rose on heavy action days, dropped on lighter ones, with protein adjusted to protect muscle. “Some people are genetically gifted. Some can eat halwa puri and still have a six-pack. But discipline is what keeps people camera-ready.”