Development The production of the film took five months from start to finish, however, Vijay claimed that the film had been in his plans for four years, but he waited for Vikram to give him dates. With
A. L. Vijay and
Vikram confirming their presence in the project, the producers failed in attempts to persuade
Vidya Balan to appear in the film. In October 2010,
Anushka Shetty agreed to appear in the lead female role in the film after agreeing terms. She had signed on in place of
Meera Jasmine, who opted out of the film before production began. Despite reports that
Divya Spandana joined the cast of the film in early 2011, Vijay refuted the claim as a rumour. The film saw the collaboration of several technicians who had worked in Vijay's earlier film
Madrasapattinam, with
G. V. Prakash Kumar as music composer,
Nirav Shah as cinematographer and
Anthony as editor. Santhanam was appointed as art director, whilst Deepali Noor took charge of costumes. Sara had appeared in a commercial for Vijay when she was two but he then lost touch with Sara's family, before he met them and cast Sara in Deiva Thirumagal, following a visit to Mumbai. The film proceeded without an official title until April 2011, with several possibilities announced during the production period. The film was tentatively titled
Deiva Magan (Son of God), a title from a 1969 film featuring
Sivaji Ganesan. However, problems arose after
Sivaji Productions claimed that they owned the rights of the title and expressed their interest on using the name for a future production featuring Sivaji's grandson,
Vikram Prabhu. The title
Pitha (Father) also ran into trouble after a debutant team announced that they had registered the title, and the title
Deiva Thirumagan also created controversies, but subsequently the film was christened as
Deiva Thirumagal in March 2011.
Filming The film was predominantly across the hill country settings in
Ooty throughout late 2010, with a chocolate factory being constructed as a set by art director Santhanam. Scenes were also shot within
Chennai, with the Chennai High Courtroom being reproduced for a scene in the film. The team of the film returned to Ooty in February 2011 to complete the final schedule, after which the film was completed. In order to perfect his portrayal of a mentally disabled adult with the maturity of a five-year-old boy, Vikram visited Vidya Sagar, a school for children with special needs, to learn and study the behavior of such children.
Marketing After completing the film with little publicity, the film met the press at
Raintree Hotel St Mary's Road in Chennai on 3 April 2011 to launch the title and logo, the teaser trailer and three twenty-second promotional videos of the film. The event was attended by technicians and actors from the film, with the teaser trailer drawing acclaim and positive reviews from film critics. ==Themes and influences==