The director had initially approached his 'Kahaani' star Vidya Balan for the lead but she declined the offer due to health reasons.
There was a buzz that Kangana was considered for the part but the actress could not accommodate her dates.
Kareena's name has been doing the rounds and the actress accepted that she was approached for the part.
"I am not doing that film. I said no," Kareena said without giving details.
There were reports that Ashutosh Gowarikar had cast Kareena opposite Hrithik Roshan in his next but the actress denied it.
The 33-year-old actress, who married Saif Ali Khan in 2012, says her priorities are different now and she wants to do only those films that suit her schedule.
"Now I am at a stage where my priorities are different. I want to do films according to my time. I am married and I want to give time (for it). I can't go on outdoor (shooting) for three months and that is the reason I rejected Zoya Akhtar's film which required me to be on a cruise for three months," Kareena said.
Zoya initially wanted real life cousins Ranbir and Kareena for her upcoming film 'Dil Dhadakne Do'.
Ranveer Singh and Priyanka Chopra play siblings in the film about a Punjabi family.
Kareena, who is shooting at Ramoji Film city for Rohit Shetty's next 'Singham Returns', will be in Mumbai today for her sister Karisma's birthday.
"Rohit is kind enough to send me back for a day. It is an important day for me... it's my sister's birthday," she said.
The actress apparently is in Bejoy Nambiar's next alongside megastar Amitabh Bachchan and Farhan Akhtar.