A huge prison set is being constructed under the supervision of National Award winning art director Thota Tharani for megastar Chiranjeevi's upcoming 150th film, which is tentatively titled "Kathilantodu"."Some of the initial portion of the film takes place in a prison. The team has been working on this set since the beginning of this month. Chiranjeevi will play one of the inmates who escapes from the prison," a source from the film's unit told IANS.To be directed by V.V. Vinayak, the film is the official Telugu remake of Tamil blockbuster "Kaththia.Chiranjeevi will be seen essaying dual roles.Ram Charan will be producing this project under his newly floated family banner.The principal shooting will commence from June 20 in Hyderabad's Ramoji Film City.