The duo would be seen together for the second time after 'Ek Main Aur Ek Tu'.
Punit Malhotra of 'I Hate Luv Storys' fame will be helming the project and it will go on floors from March this year.
"Punit wants me to look stylishly different in his film. Besides, there are five songs in the film, which require a lot of dancing. I will still be voluptuous, but the difference will be that my appearance will be more toned and fitter because I need to acquire such a look for my dance numbers," Kareena said in a statement here.
In fact, Kareena and Imran are going to rehearse their dance moves for 18-20 days before shooting the songs.
Kareena has already started working on her new look. "I used to do a lot of power yoga but have started Iyengar yoga now, which is more difficult. I have already done two sessions and I am feeling absolutely amazing," she said.
Recently, Kareena did an item number for Salman Khan starrer 'Dabangg 2' and was criticised for her weight gain.
"It was the requirement of the song ('Fevicol'). I couldn't have looked lean and toned as I was in 'Halkat jawani' (her item song in 'Heroine') because the song 'Fevicol' is a desi number."