Dia Mirza has often been at the receiving end in the past, the guinea pig of all jokes. She must never have dreamed that the usually stern Amitabh Bachchan would also get a few laughs at her expense.

While filming a long courtroom scene for Shootout at Lokhandwala recently, Dia almost fainted with fright when the Big B confronted her about a blunder that wasn't her doing.

The scene was being shot inside Elphinstone College in Central Mumbai and involved a monologue that Bachchan's character (a lawyer) had to deliver in court.

Dia, a reporter in the film, was standing near him. Suddenly, when Bachchan was halfway through his monologue, a mobile phone rang. Says a unit source, "When we heard the phone ringing, there was pin-drop silence for at least 30 seconds as everybody was stunned. Nobody dares to disturb Mr Bachchan When he is in the middle of shooting a scene.

And this wasn't even a short scene it was a three-page monologue, so all the actors required for the scene (including Sanjay Dutt, Amrita Singh, Sunil Shetty, Arbaaz Khan, Neha Dhupia and Aarti Chhabria) had been strictly instructed to put their cell phones off."

Before anybody could speak, director Apoorva Lakhia shouted at Dia to put her phone off. "Hearing which Bachchan turned to Dia and said, "Is that your phone, Dia?" and the actress almost fainted in fright, thinking she had disturbed the Big B.

Looking at the stunned expression on her face, the entire unit burst out laughing, including the Big B.

Says Dia, "The shot had to be redone, but everyone had a hearty laugh at my expense. When the shot was finally over, Sunil and Arbaaz ragged me no end!"

So whose phone was it? Assistant director Shawn Arranha reveals that Sunil Shetty had masterminded the entire prank.

Anna (Sunil) came up with this prank, and we all thought that it would be good fun to scare Dia.

Mr Bachchan knew about the prank and he was game to play along, even though he had a really long dialogue to say in the shot," says Shawn.