Hrithik Roshan and Katrina Kaif are regarded as the hottest on screen couple in Bollywood eversince their romance in Zindagi Na Milegi Dobara. According to the latest Bollywood sources say the both Hrithik and Katrina are bonding well in their upcoming film Bang Bang. Sources who watched them in the sets are surprised at their fondness to each other when they were in Manali. In Shimla too, they were seen spending lot of time speaking to each other whle shooting for a song. Sources say their bonding is growing stronger with each passing day.