Mumbai, March 14 (IANS) Celebrated author Chetan Bhagat says the trailer and songs of the film "Half Girlfriend" -- which is based on his book with the same name -- will start rolling out from end of March."'Half Girlfriend' poster, trailer, songs will all start coming out around end March/ early April," Bhagat tweeted. Co-produced by Bhagat and directed by Mohit Suri, the film stars Shraddha Kapoor and Arjun Kapoor. It has been locked for release on May 19.Bhagat added: "Absolutely extraordinary music in 'Half Girlfriend'. Best album in years hands down. Can't wait to share it all with you in a couple of weeks."This is not the first time that Arjun -- who will be seen playing the character of Madhav Jha in the film -- will be working in an adaptation. He has also starred in the movie "2 States", an adaptation of Bhagat's book "2 States: The Story of My Marriage".-*-Dia Mirza feels 'Happy birthday' song unites peopleActress-producer Dia Mirza says "Happy birthday" is sung across the world "regardless of region, religion, culture".She tweeted: "If there were one song that would be sung the world over, regardless of region, religion, culture, what would it be? I say #HappyBirthday!"On the work front, Dia will be seen in Sanjay Dutt's biopic being helmed by Rajkumar Hirani. She will play the role of Sanjay's wife Manyata.