"The Bihar government has already announced to waive off tax on the film 'Manjhi-the Mountain Man'," Kumar told reporters on the sidelines of "Janata Ke Darbar me Mukhya Mantri" programme.
The film is based on the life of Dashrath Manjhi, a poor labourer hailing from Gehlaur village in Gaya district widely known as the "Mountain Man".
He had laid a road through the mountain using only hammer and chisel in memory of his wife who passed away without medical treatment as travel to the nearest hospital took a lot of time due to the mountain.
The film is directed by Ketan Mehta. Nawazuddin Siddiqui enacted the role of Dashrath Manjhi, while Radhika Apte played Manjhi's wife.
The film is scheduled for release on August 21, 2015.
Kumar is scheduled to attend a programme on the movie in the evening.
The cast of the film paid a visit to Gaya last evening as a part of an event to promote the movie.