Actress-singer Priyanka Chopra has sung a lullaby in her forthcoming film "Mary Kom", a biopic on the five-time World Champion boxer. "I have sung a lori (lullaby) in the film, which comes in the important part of the film. It's a very intimate conversation between the mother and child and yes, it was fun. It has a good tune," said Priyanka. She was speaking at the trailer launch of "Mary Kom" Wednesday. Director Omung Kumar got ample support from Mary Kom during the making of the movie, which will release Sep 5. In the last few years, Bollywood has successfully churned out films based on sportsmen like “Paan Singh Tomar” and “Bhaag Milkha Bhaag”. Many feel that sports based films have become trendy in filmdom, but Priyanka begs to differ. She said: "This is the first film on a female athlete and it is very disrespectful to say it's a trend." (Source: IANS)