A CYNIC might say there is not a lot of difference between the average Scottish courtroom and a street full of marauding zombies – but one Scottish lawyer can boast about having had a taste of both.

Solicitor David Patterson swapped the courtroom for a glimpse of superstardom when he was picked to be Brad Pitt's body double for the zombie blockbuster World War Z, which opened this weekend, when scenes were filmed in Glasgow.

Hundreds of extras were needed to film a zombie attack in and around George Square in the city centre, as well as a disused supermarket in the south of the city.

The 26-year-old lawyer and his fiancée Amy Windsor, who live in Lasswade, Midlothian, both auditioned for parts in the film.

Patterson said: "We were through in Glasgow shopping and decided to go along to the auditions.

"All we had to do was fill out a form and get photos taken and we didn't really think we had a chance."

For a while they heard nothing – then Patterson received one of the strangest phone calls of his life.

"The call was to ask me if I could stand in for Brad Pitt and I couldn't believe it," he said.

"I was in court when I got the message and had to ask my boss if I could go, but they were very supportive."

Patterson stood in for Brad Pitt, who plays a United Nations worker in the film, when the cameras rolled in the empty Kwik Save at Cardonald.

The solicitor was asked to take on the role because his physical frame is nearly identical to that of Brad Pitt, and he is the same height as the 5ft 10in heartthrob.

"The main stand-in for Brad was doing exams down in London, so that's why they needed someone else," Patterson said.

"Brad would run through the scene, then I had to do exactly what he did about 10 or 15 times so they could get everything right.

"Then Brad would step in and do the final shots.

"He seemed really professional and very focused, so I didn't speak to him.

"I needed to appear like I wasn't star-struck, but I was."

Parts of Glasgow stood in for the American city of Philadelphia in August 2011 while key scenes for the movie were shot.

During filming, Pitt stayed at the Carnell Estate in Ayrshire with partner Angelina Jolie and their children.

World War Z, based on the Max Brooks novel, has received mixed reviews.

The Scottish premiere of the film took place in Glasgow on Wednesday at the Grosvenor Cinema in the city's west end.

Ken Creelman of the Grosvenor managed to secure an exclusive showing for the city after approaching a contact at Paramount Pictures, which made the film.

Creelman said of the premiere: "It was a fantastic night. We had a full audience and a lot of them made the effort by dressing up as zombies or in black tie.

"Most of the audience had been extras in the film, so they had obviously been keen to snap up the tickets first.

"The staff were zombified up and the film was brilliant."