Ayalaan

On 16 October 2016, Sivakarthikeyan and his former manager-turned-producer R. D. Raja of 24AM Studios, announced their next project, which will be helmed by director R. Ravikumar, in his second directorial post the release of Indru Netru Naalai (2015).[5] Sivakarthikeyan stated that "it is an ambitious project, made on a huge scale, and hence it will take time, before it goes on floors".[6] Ravikumar had to enhance the script of the science-fiction film, which took more than a year, to finalise the pre-production works. In the meantime, Sivakarthikeyan decided to concentrate on Velaikkaran as well as Ponram's untitled film (later released as Seemaraja), both produced by Raja.[7]

Post the completion of Velaikkaran, Sivakarthikeyan announced that he will officially collaborate with director Ravikumar, for the project after completing the scripting works.[8] It was reported that the project will be made on a lavish scale, with top technicians being roped in for the project.[7] In mid-January 2018, Sivakarthikeyan further announced that he will start the shooting of the film only after completing the production works of Seemaraja.[9][10] The project was reportedly produced by R. D. Raja, the actor's former manager under his banner 24AM Studios.[11] On 15 January 2018, it was announced that A. R. Rahman will compose music for the film,[12] in his maiden collaboration with Sivakarthikeyan.[13] Sivakarthikeyan described it as "a dream come true moment", on associating with Rahman for the first time.[14] The makers roped in veteran cinematographer Nirav Shah as a part of the technical crew.[15][16]

In mid-July 2019, Raja decided to back out producing the film under his own banner 24AM Studios,[17] and Sivakarthikeyan himself decided to lend financial support for the film, by producing it under his own banner Sivakarthikeyan Productions.[18] However, when the project was revived in November 2018, KJR Studios had decided to cash in the shares of Raja's productions, including this project.[19] The company eventually co-produced and distributed the film along with 24AM Studios.[19] The makers announced the film's title as Ayalaan on 3 February 2020,[20] literally translate to "alien", as the film's sub-plot is based on alien invasion.[21]

In February 2018, Rakul Preet Singh was roped in to play the female lead,[22] collaborating with Sivakarthikeyan for the first time.[23][24] In April 2018, Yogi Babu and Karunakaran were reported to be a part of the film's cast.[25][26] Later, during the start of the shoot Bollywood actress Isha Koppikar, was signed in for a pivotal role marking her return to Tamil cinema,[27] a decade after her 2001 film Narasimha.[28] Sharad Kelkar was also reported to play a pivotal role in the film, making his Tamil debut.[29][30] The makers also roped in veteran actress Bhanupriya, Kothandam and Bala Saravanan to the film's cast.[31]

Principal shooting of the film began on 27 June 2018,[32] preceded by a launch event in Chennai,[33] and the film's team headed to Gokulam Studios for a brief schedule.[34][35] Nirav Shah used the Alexa LF camera, predominantly made to shoot Hollywood films,[36] thus becoming a first Indian film to be shot using Alexa LF.[37][38] Isha Koppikar joined the shooting sets in July 2018.[39] Major portions of the film were shot in Chennai.[34]

The shooting of the film was put on hold due to financial issues, as well as Sivakarthikeyan's commitments in other projects.[40] On 18 February 2019, Sivakarthikeyan had resumed the shooting of the film in Chennai.[41][40] However, Sivakarthikeyan's involvement in the shooting of Mr. Local, Namma Veettu Pillai and Hero, delayed the project further.[42] Adding to these reasons was the financial issues, surrounding Raja's production house, 24AM Studios, which led Raja backing out of the project,[17] and Sivakarthikeyan himself decided to lend financial support for the film, by producing it under his own banner.[18]

The project was later revamped on 20 September 2019, after Sivakarthikeyan sorted out the financial issues surrounding between the producers and the financiers.[43][44] He further decided to forgo his renumeration, in order to complete the film's shoot.[45] He initially revealed that 75% of the film's shooting has been completed, and the remaining portions will be shot within 25-30 days.[46][47] The shooting was resumed on 29 January 2020,[48] with the film's team being present in Chennai.[49][50] On 9 February 2020, a report claimed that the film's team worked for 15 hours to shoot the climax sequence.[51]

The film's shooting further affected due to the COVID-19 pandemic.[52] In July 2020, the makers reported that Sivakarthikeyan will join the shooting of the film, after wrapping his commitments with Doctor (2021).[53] Later, the makers commenced the final leg of the shoot on 26 November 2020,[54] with minimal crew, adhering to the guidelines imposed by the government.[55] A special team was designated, to observe the crew, including the director and the actor abiding the COVID-19 protocol.[55] Isha and Sharad arrived in Chennai, to join the film's shoot.[56] The final schedule took place for two months to shoot.[57] It was reported that the makers planned to shoot a special song in Chennai, featuring 600 dancers in background, which will mark the film's wrap after its completion.[58] The makers planned to shoot the song within 10 days.[59] On 24 January 2021, the makers announced that the shooting of the film has been wrapped.[60][61]

In an interview with The Times of India, director Ravikumar stated that, "There have been so many films in Hollywood that have shown aliens. Even in Bollywood, there’s Koi Mil Gaya, which features Jaado, the alien. I heard that the makers had used prosthetics on an artiste to get him to resemble an alien. But here, it’s all VFX. So, when Sivakarthikeyan is shooting in real time, he really has no reference to the alien that will be seen on screen. To assist him, we’ve got a small boy to stand in front of him so that he can look at somebody and act. But the challenge will be when we sync this on the VFX screen."[56] In January 2021, it was reported that the makers need more than 10 months, to complete the visual effects, and the makers spent more than ₹40 crore for the computer graphics.[62]