The trio thrilled fans as they stopped to chat and sign autographs, with Jack telling The Sun newspaper: "The crowd are great. There's a lot of love in Leicester Square," before jokily adding: "Is that where we are?"
In the flick, the Hollywood trio play a group of egotistical pampered actors who sign up to star in an action movie about the Vietnam War. Things don't exactly go according to plan, however, when the director instead sends them to a real danger zone with only their fake weapons to protect them.
Amongst the first to check out the action comedy was Grammy-winning chanteuse Anastasia – demure in a scarlet gown. Joining the American singer were a host of British beauties, including newly-engaged model Danielle Lloyd and socialite Lady Victoria Hervey.