Actor-turned-director Atul Agnihotri says he cast brother-in-law Salman Khan in his forthcoming film "Hello" not to increase its commercial value, but because the character in the movie demanded a star like him.

Salman plays himself, a superstar, in the film that is based on the acclaimed book "One Night At The Call Centre" by Chetan Bhagat.

"Salman plays Chetan Bhagat's character in the film. But we have shown him as Salman - the film star - unlike the book which portrayed Chetan Bhagat (the narrator) as a writer," Atul told.

"I have not cast Salman because of commercial reasons or being a relative, but it was important for the role to have an actor who has a star status," said Atul.

"Hello" is Atul's second film as director after "Dil Ne Jise Apna Kaha", which released in 2004. "Hello" is slated to hit theatres Oct 10.

Though Salman does not play the lead role, he has an important role in the movie as the story begins and ends with him.

And Salman Khan fans will not be disappointed as they will get to see enough of their superstar. The two-hour movie features Salman for at least 25 minutes, said Atul.

Besides Salman, the film boasts of a large star cast including Katrina Kaif, Sharman Joshi, Sohail Khan, Isha Koppikar, Gul Panag, Amrita Arora and Arbaaz Khan.

Katrina plays a fellow traveller who narrates the whole story to Salman.

"It is through them that the whole story unfolds and they play a pivotal part in the film," said Atul.

The director maintained that he had not deviated much from the novel, except for taking a few cinematic liberties.

He explained that while books need more time to introduce characters as it has only words to communicate, cinema is different, being an audio visual medium presentation.

The film revolves around a group of call centre workers who receive a call from god. Atul said it took them nine days to film the scene where god appears as it needed special treatment.

"It is always difficult to shoot at night, but the whole scene was shot in the night, which made things difficult for us." Extra efforts went into making the scene really special.

"Lightning and thunder needed to be created. Besides, special effects were also used for the scene," said Atul, who debuted as an actor in Mahesh Bhatt's "Sir" in 1993.

Atul said he has no plans to return to the big screen as an actor.

"I had always planned to be a director and had assisted Pankaj Parasher for five years. In between, I went into acting and had a bad experience. Now I want to concentrate on direction as this was always my first choice."