Ajith Kumar is fast wrapping up his forthcoming movie 'Mankatha', which happens to be his 50th movie. The film is produced by Dayanidhi Azhagiri under the banner of Cloud Nine Movies and is directed by Venkat Prabhu. The film is left with just few portions and will hit screens on May1, 2011. Meanwhile the actor is vigorously involved in the screenwriting phase for his 51st movie 'Billa-2'. The sources reveal that the actor along with Chakri Toleti and his team of writers is shaping up the film's screenplay. As known earlier, the film is a prequel to 'Billa 2007' that was directed by Vishnuvardhan, who was supposed to wield megaphone for this movie as well. The latest reports are that Ajith Kumar is writing the screenplay and dialogues for 'Billa-2' along with Chakri Toleti and his team of writers as well.