SRK was busy rehearsing his lines with Saif Ali Khan and the crew, when he was interrupted by a phone call. A source says, "While the two were fine-tuning their script, SRK got a call and all the activity on the set screeched to a halt."
Apparently it was Suhana on the line and the doting daddy and she had a typical father-daughter conversation, while SRK's lapel mike was still attached.
The source adds, "Shah Rukh was happily chatting away with her. Suhana asked him what he was up to and he asked his daughter about her forthcoming day at school. He also asked Suhana if she was going to attend the show in the evening."
The crew was privy to their entire conversation and there were whispers about switching the mike off. And once SRK had hung up, the entire crew burst out in laughter. The source adds, "Shah Rukh Khan had no clue about what had just happened. Later, he smiled and went back to his lines."