The film was officially announced in December 2019. Principal photography commenced the same month and wrapped by early-January 2021. It was shot in Chennai and Goa. The film has music composed by Anirudh Ravichander, cinematography handled by Vijay Kartik Kannan and editing by R. Nirmal.
Doctor was released in theatres on 9 October 2021, following multiple delays related to the COVID-19 pandemic. It received positive reviews from critics, grossed over ₹100 crore and became a commercial success at the box office. A sequel was announced in 2023.
Varun, a military doctor working in the Indian Army Medical Corps, is a strict and practical person. While returning home from an operation, he receives a voicemail from his fiancée, Padmini, who urges him to call off their upcoming wedding. While enquiring about her sudden change-of-heart with her family, Padmini belittles him for being emotionally distant and apathetic. While leaving, Varun and Padmini's family learn that Chinnu, Padmini's niece, has gone missing. The family lodges a complaint with the police – which in turn appoints Bhagat, a low-ranking police officer, to monitor the family's communications.
Disillusioned with the police's sluggish progress, Varun plots to kidnap the ACP's daughter, believing that the resulting investigation will be more competent. His plan works, and the police nab almost every major criminal related to child-kidnapping. Varun singles out three criminals (Kamala Kannan, Kamesh, and Prathap), noticing that they were present around Chinnu's school at the time of her disappearance. Varun sedates them, and interrogates them by blackmailing them with the kidneys that he had apparently removed. Kamala Kannan confesses to kidnapping Chinnu and handing her over to a child-trafficking network. Varun recruits Pratap and two other gangsters, Mahaali and Killi, to assist in his investigation.
Varun's search leads him to twins Alvin and Melvin, both of whom are responsible for child trafficking and prostitution. Varun and Padmini's family confront the duo inside a Chennai Metro train, and succeed in separating the duo and abducting Alvin. Desperate to save Alvin, Melvin concedes to releasing only one girl from his group of kidnapped girls. Although Chinnu is among them, Varun demands Melvin release all the girls, despite Padmini's objections. Melvin refuses, but hints that the girls are being taken to Goa. Varun, Pratap, Mahaali, Killi, and Padmini's family follow Melvin to Goa, where they discover that the true mastermind behind the recent kidnappings is Terry, the owner of a high-end resort.
Varun orchestrates a drama, in which he has Mahaali, Killi, and Padmini act as if the duo were kidnapping her and simultaneously has Padmini's family urge Terry to find her. As per his plan, Terry traces Padmini's kidnapping down to Varun, who poses as a child trafficker masquerading as the owner of an ice-cream parlour. Varun demands Terry to give him a girl, as compensation for saving Padmini. Unknown to Terry, Varun had arranged for his friend, Colonel James Anderson and his team of commandos to apprehend Terry. Terry escorts Varun to his base of operations, located on a remote island. Varun discovers that Terry's victims are primarily underage girls. Realising that any action would endanger the kidnapped victims' and Chinnu's lives, Varun calls off the operation despite James' protests.
Determined to save the girls' lives, Varun initiates his backup plan. He negotiates a deal with Terry and Terry's father to ship a consignment of 40 girls to Don Pablo El-Fino, a Brazilian child-trafficking boss (actually Varun's father in disguise). Concurrently, Terry organises a meeting with his associates to discuss the upcoming deal; Melvin is among those in attendance. Varun discreetly orders Melvin to kill Terry; the latter's attempt to do so is surprisingly thwarted by Varun himself (in order to gain Terry's trust). Terry interrogates Melvin, learning about Alvin's abduction and that Melvin's actions were purely out of desperation. Unwilling to reveal the identity of Alvin's abductor, Melvin is killed by Terry. Later, while going through the family profiles of the twins's latest kidnaps, Terry discovers Padmini's family is among them and deduces Varun's plan.
Terry later has Varun and the family apprehended and takes them to his island, intending to kill them. However, Alvin appears, seeking revenge for Melvin's death. Alvin reveals he had abducted Terry's father and agrees to spare him, in return for letting Varun and the family, along with all the other girls, leave. After they leave, Alvin kills Terry's father to avenge Melvin's death, and Terry kills him in retribution. Elsewhere, Varun realises that he has left a girl behind and returns to the island alone. Terry apprehends Varun and plans to kill the lone girl in front of him, but is thwarted by James's team and Bhagat, who had infiltrated his base. Varun escorts the girl to safety while James's team kills Terry and his henchmen. Three months later, Padmini reconciles with Varun, and they marry in the presence of their family and friends.
In July 2019, Sivakarthikeyan contacted Nelson Dilipkumar about starring in the director's sophomore after Kolamaavu Kokila (2018) after he released a casting call. After a series of tweets, both agreed to finalise the dates soon.[5] Though it was reported that the potential film would be produced by the Indian branch of Sony Pictures in their maiden production in Tamil,[6] this proved untrue.[7] On 1 December, Sivakarthikeyan announced he would be producing the film, titled Doctor, under his own banner Sivakarthikeyan Productions, whilst KJR Studios were announced as the co-producers.[8][9][10]
In November 2019, Kavin was reported to be a part of the film's cast, but no confirmation came from the producer's side.[11]Priyanka Mohan plays the leading actress, marking her debut in Tamil cinema.[12][13]Vinay Rai and Yogi Babu joined the cast in December,[14][15] with the former playing the antagonist.[16]Archana Chandhoke's daughter Zaara Vineet made her feature film debut.[17][18] Sivakarthikeyan was reported to have shed some kilos for his role in the film.[19] Bollywood actors and brothers Raghu Ram and Rajiv Lakshman were also roped in for antagonistic roles, making their Tamil debut.[20]
Principal photography began in Chennai on 6 December 2019.[21][22] On 6 January 2020, the makers completed the first schedule, and kickstarted the second schedule. As reports stated, the makers planned to shoot one half of the film in Chennai, and the other half in Goa.[19] In February 2020, Sivakarthikeyan and Nelson went for a recce in Goa, to scout the locations for shoot.[23] The Goa, was completed by the end of that month.[24] Shortly thereafter, filming was suspended due to the COVID-19 pandemic in India and nationwide lockdown, with 80% of the film's shoot completed, as of May 2020.[25]
Filming resumed on 25 September, with minimal crew adhering to government rules and regulations. A special team was designated to observe the film crew, including the director and actor, were abiding the COVID-19 protocol.[25] The final portions of the film, including one song was expected to be completed as of November 2020.[26] Principal photography wrapped on 3 January 2021.[27][28]
The post-production process of the film officially began on 11 May 2020, after the government granted permission to resume post-production works of Tamil films.[29] The editing works of the film have been resumed during the process.[30] On 17 September, the makers started the dubbing of the film, with a traditional puja ceremony.[31] Sivakarthikeyan completed the dubbing portions of the film on 1 February 2021, thus post-production works were completed.[32][33][34]
The film's soundtrack album is composed by Anirudh Ravichander, in his sixth collaboration with Sivakarthikeyan, and second collaboration with Nelson Dilipkumar. In February 2020, Sony Music India secured the film's audio rights.[35] The film's first single "Chellamma" was composed during the lockdown.[36] The song was penned by Sivakarthikeyan himself, which had lines about TikTok being banned in India,[37] and was sung by Anirudh and Jonita Gandhi.[38] It was released on 16 July 2020,[39] and the song went viral upon its release, crossing 130 million views as of November 2021.[40]
The second single "Nenjame" was released on 28 August 2020.[41] It features a promotional video, directed by Nelson himself, featuring Sivakarthikeyan and Priyanka Mohan, shot in monochrome by cinematographer Vijay Kartik Kannan.[42] It was reported that the song will be featured as a montage in the film.[42] The third single "So Baby" was released on 26 February 2021, and is a "classical-western" fusion song.[43] The last single "Soul Of Doctor" was released on 28 September 2021 and sung by Niranjana Ramanan.[44]
The film was released theatrically on 9 October 2021, worldwide.[45] Apart from Tamil, the film was dubbed and released in Telugu under the title Varun Doctor.[46] Initially scheduled for a theatrical release in late 2020, the film was postponed as shooting and post-production processes came to halt due to the lockdown.[47] In November 2020, the makers announced for a theatrical release during April 2021, refuting rumours of a digital release.[48]
The makers announced that the film would be released on 26 March 2021,[49][50] but later postponed due to the 2021 Tamil Nadu Legislative Assembly election taking place in April.[51] Later the makers announced that the film will be scheduled to release in Eid on 13 May 2021.[52] As of June 2021, the release date of the film had been postponed indefinitely due to rise in COVID-19 cases and state lockdown in Tamil Nadu.[53]
The satellite rights of this film was sold to Sun TV Network and streaming rights were sold to Netflix and Sun NXT.[54] The film began streaming from 4 November 2021.[55]
Doctor is the third highest grossing Tamil film of 2021 behind Master andAnnaatthe along withMaanaadu.[56] It collected ₹100 crores in 25 days, becoming the first film of Sivakarthikeyan to achieve the feat.[57][58][59] The film had a phenomenal run in the United States, where it surpassed the collections of Master.[60]
Doctor received positive reviews from critics.[61]
M Suganth of The Times of India gave 4 out of 5 stars and wrote "And all along, the writing remains solid, giving us situations that might have felt implausible in a serious film but work brilliantly because of the black comedy."[62] Srinivas Ramanujam of The Hindu wrote "With his earlier film Kolamavu Kokila, the filmmaker proved that he could captivate audiences with the story of an ordinary family doing extraordinary things. He repeats the same trope in this outing, and the result: an intriguing tale of a family going to great lengths, to save a loved one."[63] Haricharan Pudipeddi of Hindustan Times wrote, "Sivakarthikeyan's new film is unlike any you've seen him in before. With dark humour, Nelson adds spice to a mundane script".[64] J. Jagannath Business Standard wrote "Like Lokesh Kanagaraj, Nelson too promises a bright future for Tamil cinema. The Tarantino-esque absurdity that he brings to the table sans pareil in Indian cinema at the moment."[65]
At the Osaka Tamil International Film Festival 2021, Redin Kingsley won the award for Best Comedian and Zaara Vineet won for Best Child Artist.[66] At the 4th JFW Movie Awards, Priyanka Mohan won the award for Best Debutante, and Zaara won for Best Child Artist.[67]