Mumbai:  Actress Taapsee Pannu says she broke down while shooting for her upcoming film "Pink" because of its heart-wrenching subject. The Delhi-set emotional thriller also stars megastar Amitabh Bachchan. Directed by Bengali filmmaker Aniruddha Roy Chowdhury, "Pink" will release on September 16. "It ('Pink') was easiest because I belong to this place (Delhi) and difficult because it (subject) was heart-wrenching," Taapsee said at the trailer launch of "Pink" here. "The two months that I was shooting for the film I was not doing anything else except this movie. I had a breakdown on the sets as well. I started feeling for my character. It was extremely impactful. It did affect me personally and was very challenging," she said. The 29-year-old actress feels "Pink", which is produced by Shoojit Sircar, will prove to be a landmark in her career. "I did 'Baby' and now 'Pink'... That perception (of cute and bubbly) changed. I don't think people today look at me as cute and bubbly Taapsee. It will be a landmark film in my career." The actress said she feels grateful towards Shoojit for casting her in the movie, giving her a golden opportunity to act alongside Bachchan. "The fact that I got to work with Mr Bachchan so early in my career and with Shoojit Sircar is great. It was fun working with Mr Bachchan. I am thankful to Shoojit for having me in this film. He gets the best out of you. To be standing in the same frame with him (Bachchan), I better be good " she said. There were reports that Taapsee will be seen in a prequel to "Baby". To this the actress said, "Wait for Neeraj Pandey (director of 'Baby') to announce it."