Brad Pitt waves as he leaves the set of 'World War Z' near George Square, Glasgow on Wednesday. (AP Photo/Andrew Milligan/PA Wire)
The US actor was in the city this week to shoot the zombie horror movie, which is based on a book by Max Brooks.
Paramount film studio has made every effort to keep the movie under wraps. The set is closed to all media and no production details have been released.
The centre of Glasgow has been transformed to depict Philadelphia in the aftermath of a war between humans and zombies. Shooting is expected to last two weeks.
The Glasgow Film Office says the movie involves almost 1200 people and will pour over 2 million pounds ($US3.3 million) into the local economy.
