The fun film, directed by Aanand L Rai of "Strangers" fame, has Kangana paired with R Madhavan.
"It was after much deliberation that Kangana was finalised for the role. The character that Kangana would be playing in 'Tanu Weds Manu' is such that it is of paramount importance to get the casting right," Rai told IANS.
Kangana, who has played a traumatised women in most of her films, was signed on for her first comic role by Anil Kapoor for his production "No Problem", a comedy directed by Anees Bazmee.
Before venturing into comedy, Kangana did a series of serious films.
While she was haunted by ghosts in "Raaz - The Mystery Continues", "Fashion" had her playing a supermodel who fell to drugs and abuse. "Life In A... Metro" showed her in a turbulent affair with a much married boss (Kay Kay Menon), "Woh Lamhe" had her play a schizophrenic while in "Gangster" she played an alcoholic moll to a gangster (Shiney Ahuja).
Director Rai, however, is confident that she will pull off the role in "Tanu Weds Manu".
"Yes, I have studied her filmography quite closely and I know for sure that 'Tanu Weds Manu' would finally showcase Kangana in a different light. There is a definite humour to the film which thankfully is poles apart from life vs death roles that Kangana has played in the past," he said.
Explaining the reason behind finalising Kangana, Rai said: "When I was narrating the film to her, she came across as someone who was very passionate and energetic when it came to films. Moreover, what worked for me was the fact that she was taking a personal view on the subject. Now that's the kind of girl I wanted for the film since I wanted her to add something of her own to the character as well."
But before Kangana, Rai had approached Konkona Sen Sharma but she couldn't accept the offer due to date problems.
"There were genuine date issues due to which Konkona couldn't come on board. We are looking at shooting the film in the months of September, October and November but she is unavailable then. However, I'm happy about Kangana now being signed for the film since she and Madhavan coming together would be really special for the film."
Rai had earlier made "Strangers", a thriller that had Jimmy Sheirgill and Kay Kay Menon.
"After working on 'Strangers', it is nice to be working on a light-hearted entertainer with a sensitive love story at its heart. The film has an interesting soul while going well with the commercial aspects of things. I would be travelling across my locations through the next few days and begin shooting in September," he said.
The filmmaker said his movie would be shot in places like Lucknow, Kanpur, Faridkot, Patiala and New Delhi.