Roman Catholics in the Indian city of Mumbai (Bombay) have received Muslim support in protests against the release of the movie, The Da Vinci Code.
Audrey Tautou and Tom Hanks star in The Da Vinci Code film
Film censors have cleared the movie for release in India on 19 May.
An umbrella organisation of Islamic clerics in Mumbai have labelled the film as "blasphemous" because it spreads "lies" about Jesus Christ.
One Roman Catholic activist has gone on what he says is a "hunger strike until death" unless the film is banned.
"The Holy Koran recognises Jesus as a prophet. What the book says is an insult to both Christians and Muslims," Maulana Mansoor Ali Khan, general secretary of the All-India Sunni Jamiyat-ul-Ulema, told the Reuters news agency.
The Da Vinci Code has generated controversy around the world
"Muslims in India will help their Christian brothers protest this attack on our common religious belief," he said.
His stance was supported by Syed Noori, president of Mumbai-based Raza Academy, a Muslim cultural organisation that organises protests on issues concerning Islam.
"If the government doesn't do anything, we will try our own ways of stopping the film from being shown," he said. "We are prepared for violent protests in India if needed."
A Roman Catholic activist, Joseph Dias, began a hunger strike on Tuesday which he said would be continued until the film is banned.
Earlier this month hundreds of Catholic demonstrators gathered outside a convent school in Mumbai in protest over the film's release.
Da Vinci Code author Dan Brown explores the premise that Jesus married Mary Magdalene and produced children, whose descendants are alive today.
The Catholic Secular Forum has described the film as "offensive" because hits "certain basic foundations of the religion".
India's Central Board of Film Certification said Tuesday it would give the movie an adult rating if the film-makers agreed to a disclaimer at the start of the movie saying it was a work of fiction.
"There is a visual of self-flagellation and limited amount of nudity in (one) particular scene," board member Vinayak Azad told the AFP news agency. "It has got adult content."
One of the three Catholic representatives of the five-member board, the Rev Myron Pereira, said that it was cleared because the contention that Christ married was "fictional".
"But it does not portray anything in an obscene fashion," he said. "People can protest about anything since we live in a democracy."
It is estimated that there are about 18m Roman Catholics in India, with 500,000 living in Mumbai. The Christian community comprises about 2% of India's population of over one billion.