Rajkumar Gupta's maiden directorial project was Rajeev Khandelwal's Bollywood debut "Aamir". While the filmmaker has now started working with known names like Vidya Balan and Emraan Hashmi, he says having stars doesn't guarantee the success of any film.

"Star system was always there in our country, but it depends on the subject of the film. Stars don't guarantee the success of any film. Yes, certainly there is no denying that they have a strong box office appeal, but they don't guarantee a good film," Gupta told .

He worked with Vidya and Rani Mukerji in "No One Killed Jessica", and his forthcoming film "Ghanchakkar" features Vidya and Emraan Hashmi.

"As far as my choice is concerned, I cast Vidya and Rani in 'No One Killed Jessica' because that was the demand of the script. It all depends from script to script," he added.

Gupta says Vidya is a thorough professional.

"Post 'No One Killed Jessica', I wanted to work with her again, but I needed a strong script to convince her. She is a thorough professional and I am glad that she agreed to do 'Ghanchakkar'," said Gupta.

"Ghanchakkar" is a comic entertainer, releasing Friday.