Chandramukhi was produced by Prabhu and his brother Ramkumar Ganesan through their company Sivaji Productions, and is the company's 50th film. The soundtrack album and background score were composed by Vidyasagar. Cinematography was handled by Sekhar V. Joseph and editing was done by Suresh Urs. Principal photography began on 24 October 2004 and was completed in March 2005.
Chandramukhi was released on 14 April 2005 on the eve of the Tamil New Year. The film became a major box office success, with a theatrical run of 890 days at Shanti Theatre. The film won five Tamil Nadu State Film Awards, four Film Fans' Association Awards and two Filmfare Awards. Jyothika and Vadivelu were each awarded a Kalaimamani Award for their work on the film. A sequel Chandramukhi 2 was released in 2023.
Saravanan, a renowned psychiatrist from the United States, comes to visit his best friend Senthilnathan and his wife Ganga while on holiday. Senthil's mother Kasthuri wanted Senthil to marry Priya, the daughter of his father's cousin Kandaswamy, to reunite the two branches of the family after 30 years of separation because Senthil's father chose to marry Kasthuri instead of Kandaswamy's sister, Akhilandeshwari, who is also his cousin. Saravanan learns that Senthil had bought the Vettaiyapuram mansion, despite attempts by the local village elders to dissuade them, and moves in with them. Akhilandeshwari is jealous of Saravanan and plots to get rid of him with the help of her assistant Oomaiyan.
When the family visits their ancestral temple, the chief priest reveals the reason everyone fears the mansion. Around 150 years ago, a king named Vettaiyan travelled to Vizianagaram in Andhra Pradesh, where he met and lusted after a dancer named Chandramukhi. However, she did not reciprocate his feelings as she was already in love with another dancer named Gunasekaran. As a result, Vettaiyan took her back to his palace by force. Unknown to him, Chandramukhi made arrangements for Gunasekaran to stay in a house opposite the mansion and met him secretly. When Vettaiyan discovered this, he beheaded Gunasekaran on Durgashtami and burnt Chandramukhi alive. As a result, Chandramukhi's spirit started haunting the entire palace in a desperate attempt to kill Vettaiyan. Vettiyan however summoned high priests and powerful sorcerers from all over the country who were successful in sealing Chandramukhi's tormented spirit, keeping it confined in a room located in the palace's south-west corner and guarded by a large king cobra. Vettaiyan too died after a few years. Back at home, Priya is in love with Vishwanathan, a dance professor who reciprocates her feelings. Their love is supported by Saravanan, who requests Kandaswamy to arrange their marriage.
After hearing Chandramukhi's story, Ganga, who thinks that the story was fabricated to keep thieves from stealing treasures in the room, wishes to go there. Saravanan receives an email to attend a patient and assures Senthil to call him if anything happens before leaving. Ganga works with the gardener's granddaughter Durga to forge a duplicate key to Chandramukhi's room and successfully opens the door hereby breaking the seal and releasing Chandramukhi's spirit. Subsequently, strange things begin to happen in the household: a ghost frightens the people in the house, things inexplicably break, and Ganga's sari catches fire. Suspicion turns towards Durga as she spends the most time with Ganga. Senthil immediately calls Saravanan to solve the case and as soon as Saravanan returns, a mysterious being tries to kill Priya. Saravanan also investigates other incidents such as the attempts to kill Senthil made by poisoning his coffee and pushing a glass fish tank off of a balcony to fall onto his head. Meanwhile, every night, Saravanan can hear the sound of someone singing and dancing from upstairs in Chandramukhi's room.
On Durgashtami, before carrying out his plan, Saravanan asks Senthil to trigger Ganga and see for himself whether she turns into Chandramukhi or not. When Senthil does so, she turns into Chandramukhi, which shocks him. A worried Senthil shouts at Ganga, stunning her back to normal. She falls unconscious and Senthil lets her rest, but once left alone, Saravanan, Senthil and Vishwanathan can hear the sound of Bharatanatyam anklets coming from the mansion's dance hall. They bring the family there for Ramachandra Acharya's rituals, where he allows Ganga, to burn Saravanan alive. Ramachandra Acharya then blows smoke and ash on Ganga's face when she is given a torch to burn Saravanan, distracting her momentarily. Senthil then opens a trapdoor to let Saravanan escape, and an effigy of Vettaiyan gets burnt instead. Convinced that Vettaiyan is dead, Ganga stops imagining herself as Chandramukhi, curing her. The large cobra protecting Chandramukhi's spirit too leaves the palace as a result. The two families are reunited after 30 years, and Saravanan lets them know that him and Durga have been in love for a long time. Durga leaves happily with Saravanan, and the couple Swarna and Murugesan become parents after eight years of marriage.
Four weeks ago, [Rajinikanth] called me on a Sunday afternoon, and asked what I was doing. I told him I had had [sic] a lot of biryani and was spending time with my sons! He laughed in his stylish way, and then asked if I was doing any new production. I told him we are thinking of doing a Hindi film with Rajkumar Santoshi in March. [...] I was quite free at the time. That's when he asked me, 'Shall we do a film, Ramu?' It came as a pleasant surprise. On a Sunday afternoon, after a heavy lunch, this suggestion from Rajnikanth was like superb dessert! I said, 'I am very happy sir.' He told me he had heard a subject, and we would make a film on that.
During the success meet of Mannan (1992), Rajinikanth announced that he would act in Sivaji Productions' 50th film,[9] which would eventually become Chandramukhi.[10] In September 2004, Rajinikanth congratulated P. Vasu on the success of his Kannada film Apthamitra (2004) and was impressed with the film's screenplay. Vasu then requested to remake the film in Tamil with Rajinikanth, who in turn, called Ramkumar Ganesan and asked him to produce it under Ramkumar's banner, Sivaji Productions.[11]
Ramkumar telephoned Vasu, who was offering worship in a temple in Guruvayur at that time, informing him of Rajinikanth's wish to do Apthamitra in Tamil under his direction.[11] Vasu reworked the script he wrote for Apthamitra to suit Rajinikanth's style of acting.[12] The film dealt mainly with the concept of dissociative identity disorder, commonly known as "multiple personality disorder" (MPD) or "split personality disorder". Another film titled Anniyan (2005), which was released two months after Chandramukhi, was also based on the same disorder.[13]
Thota Tharani was the film's art director,[11] and also designed the costumes.[14] Regarding the designing of the Vettaiyapuram palace, he watched both Apthamitra and its source Malayalam film Manichitrathazhu (1993) to get the basic idea of the film's plot. Vasu wanted Tharani to make the sets more colourful and grand and did not want the realistic look of the original film. Tharani designed Chandramukhi's room and placed a corridor in it, which was noticeably different from the original and its Kannada remake. The corridor resembled those commonly seen in palaces in Kerala.[14] Sidney Sladen did additional costume designing in the film.[15]
Rajinikanth played the roles of Dr. Saravanan and King Vettaiyan. He sported a wig for his role. Both Rajinikanth and P. Vasu discussed every scene featuring the former and added necessary inputs before they were shot.[16] Rajinikanth appears in the beginning of the film unlike Manichitrathazhu, where the same character, played by Mohanlal, appears in the middle of the film.[17] Rajinikanth requested Vasu to change the dancer's name from Nagavalli, which was the name of the danseuse in Apthamitra, to Chandramukhi since the latter sounded more royal. While Vishnuvardhan uttered "Haula Haula" in the original, Rajinikanth used "Lakka Lakka", which was based on the mannerisms of a villain in a Marathi play Rajinikanth watched in his childhood days.[9] Ramkumar's brother Prabhu played Senthilnathan, a civil engineer and owner of the fictional Ganesh Constructions. Prabhu co-produced the film with Ramkumar.[18]
For the roles of Ganga and Chandramukhi, Soundarya was initially selected to reprise her role from Apthamitra, but her death led the director to choose Simran and he shaped the character to suit her. In November 2004, Simran refused to do the project, as her role required a lot of dancing and cited her pregnancy at that time as another reason for her refusal.[19] Aishwarya Rai was offered the role but she declined the offer due to scheduling conflicts.[20] Sadha, and Reema Sen were also as replacements.[19][21] The role finally went to Jyothika, who allotted 50 days of her schedule.[22] Vasu wanted her to perform her scenes in a manner different from that of Shobana in Manichitrathazhu, enacting the scenes himself before they were shot featuring Jyothika.[23] Nayanthara was selected to portray the role of Durga after Vasu was impressed with her performance in the Malayalam film Manassinakkare (2003).[17]
Vadivelu portrayed the comic role of Murugesan. Rajinikanth, at the film's 200th day theatrical run celebration function, said that it was he who recommended Vadivelu to Vasu for the role and had asked Ramkumar to get Vadivelu's dates before planning the filming schedules.[24] Sheela played Akhilandeswari, the intimidating older sister of Kandaswamy (Nassar) and Murugesan. When Sheela was signed on for the role, she was requested by the producers not to divulge details about her role to the media.[25] Avinash reprised his role of the exorcist Ramachandra Acharya who talks with the spirit Chandramukhi from Apthamitra.[26]