Fast on Friday) is a 1974 Indian Tamil-language devotional film, directed by R. Thyagarajan in his debut and produced by Sandow M. M. A. Chinnappa Thevar under Dhandayudhapani Films.

[2] The film stars Sivakumar, Jayachitra and Jayasudha, along with Nagesh, Sundarrajan, Srikanth and Sasikumar as supporting actors.

The film was remade in Telugu as Nomu (1974)[3] and in Hindi as Shubh Din (1974).

[6] The film's story was written by Sandow Chinnappa Thevar inspired from the films The Shadow of the Cat and Cult of the Cobra who initially created a plot revolving around a child and snake since Thyagarajan wanted romance, a new plot was formed.

Thyagarajan revealed sound overlapping system technology was used in the film.