Actor-filmmaker Kamal Haasan on Monday said Tamil filmdom will speak with "one voice" on the ongoing cinema theatres shutdown in the state following the government's decision to levy 30 per cent entertainment tax over the newly implemented GST.The Goods and Services Tax came into effect from July 1.Speaking at the launch of a dubbing studio here on Monday, Kamal told the media: "The entire industry is gathering together and we shall speak as one voice soon."Theatres across Tamil Nadu have been shutdown from Monday in protest against the double taxation.On June 30, Abirami Ramanathan, President of the Tamil Nadu Film Chamber of Commerce, said the government should fall in line with the other southern states' tax slab.While a Rs 100 ticket in the neighbouring states (Kerala, Andhra Pradesh, Telangana and Karnataka) would cost Rs 118 post-GST, it would cost Rs 148 in Tamil Nadu, thanks to the government's additional 30 per cent state tax on the ticket.