Bollywood actor Ranbir Kapoor may have earned heartthrob status with his romantic roles but the actor is thrilled about his forthcoming flick 'Rajneeti'.

In'Rajneeti', Ranbir essays the character of "a grown-up man" for the first time.

The actor said, "I have usually acted in coming-of-age dramas or done lover boy roles in my films so far but Rajneeti is my first mature role. It is a dark political thriller and also my first character with grey shades."

Inspired by 'Mahabharata', Rajneeti is a caustic remark on the country's political structure.

The film stars Arjun Rampal, Vivek Oberoi, Nana Patekar, Manoj Bajpai, Katrina Kaif and Ajay Devgun.

Ranbir, who recently finished his shooting in Bhopal, is very much happy to be a part of Prakash Jha's grand project.

While discussing about the movie, which is based on the Madhya Pradesh political sympathies, the actor said, "It was really great to work with Prakash Jha. He is one of the great directors in the industry and has contributed a lot to Indian cinema. The film has a great ensemble cast. We just finished the shooting," the actor says about the film, which is based on the Madhya Pradesh politics.

Ranbir, who will be seen romancing with Katz again in 'Ranjneeti' after Ajab Prem…, describes the Bollywood doll as exceptional.

"Katrina is phenomenal. She has this undying energy on the set. She is so successful but never takes it for granted. From not knowing the language to becoming one of the biggest star, she has achieved a lot. I have tremendous respect for her as an artiste," Ranbir said.