Shivam Rao, who wowed audiences and critics alike with his production design in India's first submarine-based war drama "Ghazi", has been signed on for upcoming bilingual drama "Mahanati", a biopic on legendary southern actress Savitri."Shivam is on board. I was mighty impressed by his work in 'Ghazi'. Our film too will be made on a big scale and it requires extensive art work, especially to recreate long forgotten era and his expertise will come in handy," the film's director Nag Ashwin told IANS."It will be a magnum opus period film set in the golden era. With massive set pieces, the film will be unlike anything we've explored in Indian cinema," he said.Keerthy Suresh will play yesteryear star Savitri in the film, which also stars Samantha Ruth Prabhu, Dulquer Salmaan and Vijay Deverakonda.Talking about the project, Ashwin added: "Most of the pre-production work has been completed. We start rolling from this month-end. Mickey J Meyer has signed to take care of the music."The film will be made in Telugu and Tamil.