Siruthai
Theatrical release poster
Directed by	Siva
Written by	Siva T. Senthil Kumaran M. Chandran (dialogues)
Screenplay by	Siva
Story by	V. Vijayendra Prasad
Based on	Vikramarkudu by S. S. Rajamouli
Produced by	K. E. Gnanavel Raja S. R. Prakash Babu S. R. Prabhu
Starring	Karthi Tamannaah Bhatia Santhanam
Cinematography	R. Velraj
Edited by	V. T. Vijayan
Music by	Vidyasagar
Production company	Studio Green
Distributed by	Studio Green
Release date	14 January 2011 (2011-01-14)
Running time	160 minutes
Country	India
Language	Tamil
Budget	₹11–13 crore[1][2]
Box office	₹30 crore[citation needed]

Siruthai (transl. Cheetah) is a 2011 Indian Tamil-language action comedy film directed by Siva, who is also one of its co-writers. It is a remake of the 2006 Telugu film Vikramarkudu, directed by S. S. Rajamouli. It stars Karthi playing dual roles, alongside Tamannaah Bhatia and comedian Santhanam. The film was produced by K. E. Gnanavelraja and features music by Vidyasagar. The story revolves around "Rocket" Raja, a petty thief who comes across a little girl says that he's her father. When he learns the truth about his lookalike Rathnavel Pandian, who's an honest cop, he decides to turn a new leaf and help get rid of a crime gang.^[3]

It was released during Pongal on 14 January 2011. Generally the film got positive responses, and was a success at the box office.^[4][5] The film was remade in Bengali-language in 2012 as Bikram Singha: The Lion Is Back.^[6] In 2024, the film made its official debut on Blu-ray in the United Kingdom.^[7] The success of the film led to the director Siva being known as "Siruthai Siva" from then on.^[8]

Rocket Raja is a pickpocket in Chennai who steals anything he comes across with his partner, Kaatu Poochi. He enjoys his life to its fullest and goes to rob a marriage function. There, he meets Swetha, and they both fall in love. However, his life changes when a small girl named Divya Rathinavel ends up in his care; she says that Rocket Raja looks exactly like her father, DSP Rathinavel Pandian IPS.

Ratnavel's colleague informs Raja about the girl's past. Rathinavel is an honest policeman who is a nightmare to criminals. The gang of criminals in the village of Devi Pattinam, Andhra Pradesh, are intent on killing him and his daughter because he killed the son of a prominent criminal, Bavuji, who also sexually abused women. Rathinavel's colleagues put Divya in Raja's care so the criminals could not take her. Rathinavel is on the verge of death following a gunshot to his head.

At first, Raja is angry with Divya and breaks her tape recorder. Divya is happy and hugs him after he repairs it. When Swetha comes to Raja's home with her parents, she sees Divya and thinks that she is the daughter of Raja and breaks up with him. Rathinavel is intent on fighting back. Unfortunately, he dies following a battle with several criminals chasing Raja and Divya. After finding out about Rathinavel from the police officers, Raja realises that Rathinavel was an honest and courageous police officer who stood against Bavuji and his family, who had cruelly ruled a village. Rathinavel even manages to make his son die and stop their criminal acts. He also manages to fail Bavuji's brother, Badra, but he gets shot when he tries to save a child.

Upon seeing his courage, Raja, with the help of Rathinavel's colleagues, steps into Rathinavel's shoes and finishes his unfinished work as he is a thug and destroys all their properties with the help of Kaatu Poochi in a hilarious way. There, Swetha sees Raja, but he tries to escape from Swetha because he is now Rathinavel, so Swetha seduces him, which he tries to control himself but to no avail. She apologises to him for learning the truth about Divya & her father, Rathinavel, and they reconcile. Raja then resumes his mission, kills the baddies and takes on the responsibility of caring for Divya with Swetha's help.

In 2008, reports emerged that Vikramarkudu would be remade in Tamil with Karthi. Anushka, who acted in original, was considered for the female lead. Suraj of Thalai Nagaram was said to be the director.^{[citation needed]} V. V. Kathir who directed Jiiva starrer Thenavattu was also announced as director but Sivakumar advised Karthi to do strong characters before making a mark as action hero thus the project was dropped.^{[citation needed]} The project was revived in 2010 and Siva, who directed films like Souryam and Sankham, was selected as director making his debut in Tamil.^{[citation needed]} Tamannaah Bhatia was chosen as heroine after Paiyaa.^{[citation needed]}

The soundtrack album to the film was composed by Vidyasagar and features five songs. It was described as "bland" by Rediff.com,^[9] while Sify called it "catchy and youthful".^[10]

Sify claimed that Siruthai had "come out as a festival bonanza for Tamil film goers. It is an unpretentious commercial pot boiler with ample doses of romance, comedy, action and emotion".^[10] N. Venkateswaran from The Times of India deemed a score of 2.5/5, citing that it "does not do anything for Karthi as an actor; what it does is to cement his position in the Tamil film industry as an actor who is a big draw at the box office".^[11] Malathi Rangarajan from The Hindu noted: "Generally, well-told cop stories don't bite the dust. Nor do dual role bonanzas. Going by the norm, this Siruthai should charge ahead!"^[12]

• Siruthai at IMDb