Ever wondered what the secret of Bollywood brat, Salman Khan's physique is? According to Arbaaz Khan, its pure passion. "For Salman, exercising is his passion. He doesn't look at it as something he has to do for X reasons. He just loves it," reveals his brother. And what about him? Is he into fitness, like his brother? Arbaaz gives that sheepish grin which indicates he has been caught on the wrong foot. After all, he is in the business of looking good, besides being fit and trim. "I am into fitness," he admits, "but I tend to get lazy. I need to be given a little whack on my backside sometimes," he adds. And that whack comes from Sallu bhaiya. "Sometimes he tells me that I should not take it too lightly. But I have a tendency to put on weight even when I see food," laughs Arbaaz. "I need to get my act together where my exercise regime is concerned. Sometimes I'm at the gym for three months and then I take a break." Well, considering his wife Malaika Arora is in great shape even after giving birth to Arhaan, Arbaaz better get his act together. Or else you might just find Sallu bhai giving him that much needed push from behind