The film is about the two look-alike twins who were separated at birth. One being a coward while another one being a courageous man. The rest of the film revolves around the twins whose paths are crossed when they meet each other. Shooting was mostly held at Vijaya Studios. The film was released in 1965 and ran for over 175 days in 7 Theatres (Chennai - 3, Madurai, Kovai, Trichy and Thanjai) and 100 days in 13 theatres, which was a record till 1979. This industrial record in terms of collection was beaten by Adimai Pen four years later. The film ran 25 weeks in chennai. This movie was taken in Eastman Color
Ramu (MGR) is an innocent & cowardly one – the heir to all riches of Poonjolai Jamin. He has been raised that way by Susheela (Pandari Bai) and his sister's husband Narendran Gajendran (M. N. Nambiar). Ramu shivers at the very mention of his brother in law's name and a whiplash is Narendran's favorite form of punishment. Narendran wants to get Ramu married to Leela (B. Saroja Devi) for her wealth and he demands dowry, but she is turned off by his cowardice.
Narendran plans to take all off Ramu's wealth and kick him out of the house. Ramu over hears this and runaway.
Ilango (MGR) is a jobless young man, prone to pick a fight and for this reason, he cause trouble for his mother(Rushyendramani). Ilango chase a thief who steal Leela's purse and Leela takes him home mistaking him as Ramu. Ilango enjoys their attention and does not reveal his true identity to them.
Meanwhile, Santha a village girl finds Ramu who is now unconscious due to hunger and bring him home to his mother Rushyendramani. Ilango teaches a lesson to Narendran while Ramu learns the ways of the world.
Narendran is angered as Ilango interferes in factory matters and made him powerless in front of the workers. He beats his wife susheela accusing her for encouraging Ilango. A fight ensues between Ilango and Narendran, Narendran leave the house with his sister and daughter, Meena.
Due to this, Susheela fall ill and Narendran rejects Ilango's request to come home. Ilango decides to leave and reveal that he was not Ramu through a letter to Narendran. Narendran kidnaps Govindan who is a friend of Ilango and get to know about his whereabouts. Narendran's goons kidnap Ramu mistaking him for Ilango.
The rest of the story reveals that Ramu and Ilango are brothers who got separated during their childhood. Ilango was adopted by a childless couple. Ilango comes to rescue Ramu and after a fight Narendran see them together and have a change of heart.
The film ends happily with Ramu marrying Santha and Ilango marrying Leela with the blessings of Narendran and all family members.M. G. Ramachandran as Ramu/Ilango
B. Saroja Devi as Leela Ranganadhan Pilai
S. V. Ranga Rao as Ranganadhan Pilai, Leela 's father
M. N. Nambiar as Narendran Gajendran
K. A. Thangavelu as Malaiyappa
Nagesh as Govindhan, Ilango 's friend
Rathna as Santha
Pandari Bai as Susheela, Narendran Gajendran 's wife
L.Vijayalakshmi as The female main dancer of "Kankalum Kaavadi..."
Madhavi as Randji, Malaiyappa 's daughter
Seethalakshimi as The older sister of Narendran Gajendran
Rushyendramani as Ilango 's mother
Baby Shakila as Meena, Narendran Gajendran 's daughter
The film was a remake of the 1964 Telugu film Ramudu Bheemudu which had N. T. Rama Rao in the lead role. Tapi Chanakya who directed the Telugu version has also directed Tamil version. Sakthi Krishnasamy wrote the dialogues for the film. A. Vincent was recruited as the director of photography and C. P. Jambulingam edited the film.
The makers were set deadline by producers to complete the film within 45 days to release it in Pongal. Sets were erected in all the floors at Vauhini Studios. For the scene involving both MGR who cross each other, cinematographer A. Vincent used lighting mask technique to shoot the scene.
Once during the shooting, the director found the actors struggling with the words, the director asked Sakthi’s assistant to change the words, despite MGR warning him not to. Sakthi heard this, came to him took the dialogue papers, tore them and walked away saying no one can change his dialogues. MGR who watched all this with a smile called the director and told him to go to the writer’s house to apologise. Sakthi came back and wrote dialogues that were agreeable to all. Raja Sandow, wrestler appeared in a small role in the film, his scene in the film is based on the real life incident happened in his life during his experiences of his first stint at acting. MGR who came to know about the incident incorporated it in the film. During the shoot of a duet song. producer B. Nagi Reddy expressed disappointment that the costumes and lyrics were not jelling well in one stanza of a song, during next day MGR completed the shots and Nagireddy was surprised seeing the involvement of Ramachandran.
The soundtrack album was composed by Viswanathan–Ramamoorthy and the lyrics were penned by Vaali and 'Alangudi' Somu. The soundtrack was released under the label Saregama. The song "Naan Aanaiyittal" had two versions; the film version had word "Kadavul" (God) and Ramachandran did not agree to use the word but later relented after requested by Vaali, lyricist of the song, but it got changed into the word "Thalaivar" (Leader) in audio records.
G. Dhananjayan in his book Best of Tamil Cinema mentioned that the film's memorable songs "ensured repeat audiences". The song "Naan Aanaiyittal" remains one of the famous songs from the film. The song "Kumari Pennin" was remixed by Srikanth Deva in Perumal (2009).
The film was released on 14 January 1965 on the festival of Pongal and emerged as a major box office success broke all previous records and celebrated Silver jubilee in 7 theatres. MGR's duel roll as Heroic and coward, which pulled public to theaters irrespective of fans. Normally no film is considered for National Award if it is remade from other language but this movie was selected for award because of its commercial value. Indiaglitz stated "Enga Veetu Pillai was an out of the ordinary film which increased the fan base of MGR to numerous folds. Enga Veetu Pillai became an aspiration for many would be Tamil Cinema heroes and a cult classic with MGR fans". Tamil magazine Ananda Vikatan dated 24 January 1965 mentioned "It is the best film which we have seen in Tamil cinema on the theme of an imposter... the film has newness in its scenes... Overall it is a film which entertains the audience and occupies a special place among the good films in Tamil cinema".
The film inspired several later films in Tamil which focused on the theme of look alike twins separated at birth and then crossing their paths when they grow up. The films which followed similar theme were Vani Rani (1974), Kalyanaraman (1979), Thoongadhey Thambi Thoongadhey (1983) and Rajadhi Raja (1989). The Hindu included "Naan Aanaiyittal" among lyricist Vaali's best songs in their collection, "Best of Vaali: From 1964 - 2013". Behindwoods included the "MGR's whip" from the film in its list of "Best accessories used in Tamil Cinema".
The songs from the film has inspired film titles - Naan Aanaiyittal (1966), Kumari Pennin Ullathile (2010). The footage of song "Naan Aanaiyittal" has been intersposed in Villu (2009). The basic story line of Seeta Aur Geeta (1972) was noted for its similarity with Enga Veettu Pillai as its female lead, portrays identical twins instead of male. This prompted Chakrapani to remake the film in Telugu and Tamil as Ganga Manga (1973) and Vani Rani (1974).
In 2009, director Badri's new film Thambikku Indha Ooru, was initially titled Enga Veettu Pillai but this was changed as the producer could not get the rights to use the same. One of the song sequences from the film had 80 feet huge cut-out of MGR in the get up which appeared in Enga Veetu Pillai. The Telugu film Nene Raju Nene Mantri was dubbed in Tamil as Naan Aanaiyittal, named after this film's song.