The production company is said to have taken the measure after still images of the actors and video content from the shoot emerged during the earlier UK schedule in March.
© Yash Raj Films
"Yashji was concerned that the look of the film would be given away, as there's already a lot of leaked photos and footage from the film on the net and on YouTube," said a production source.
"This time we have asked artistes to either leave their phones at home or deposit them with security and collect after pack up."
Shooting on the project has resumed in the UK, with actor Anushka Sharma joining the team for the second schedule.
Yash Chopra has just released a new image from the film, which shows Khan and Sharma on a bike riding through the streets of west London.
Much of the filming took place in central London locations during the first schedule, but YRF has reportedly been shooting outside the capital on the second schedule.
