Take-off for a film is not particularly easy, especially when it involves big stars or a huge budget; Movie-buffs have been witness to every production issue from films getting dropped before shoot to projects stalling from a financial hustle or unavailability of an actor. There have even been cases of films waiting in the pre-production stage for years only to get shelved later.

And here, we have listed out some popular Tamil films which has dealt with casting changes of lead actors mid-production and looking at the numbers, it seems like this isn't an uncommon prevalence in Kollywood. 

1. Unnai Ninaithu

The film initially had Vijay in the lead and the team went on to shoot for few days, but for unknown reasons Vijay opted out, Suriya came on board and the film turned out to be a huge success.

2. Aadukalam 

National award winning Aadukalam initially had Trisha playing the female lead role. The film was halted midway due to financial hurdle and when it resumed later on, Trisha's dates were booked thus bringing in Taapsee.  

3. Nerukku Ner

Vasanth's Nerukku Ner could have been a memorable film for both Ajith and Vijay had it gone on as planned. For reasons unknown, Ajith opted out of the movie and then-newcomer Suriya ended with a dream debut in the Tamil film industry.

4. Friends

Vijay and Suriya starrer friends had Jyothika and Suvalakhmi as female leads but were replaced by Devayani and Vijayalakshmi mid-production. Film went on to be a super hit.

5. Achcham Yenbadu Madamayada

In later 2013, actress Pallavi Subhash had shot for Gautham Menon's Achcham Yenbadhu Madamaiyada as the fim's female lead. But Menon's focus on other projects caused a filming delay and Manjima Mohan became the female lead of the movie in 2015.

6. Ghajini

The story of Ajith and Asin signing on for an A.R. Murugadoss directorial called Mirattal only for Ajith to opt out later-on is a famous one in Kollywood. After 3 months of the Mirattal getting shelved, Suriya was brought on as the lead and the project was revived as Ghajini. 

7. KO 

Actor Simbu was signed on as the lead of K.V. Anand's Ko when news of rift between the actor-director surfaced. The word then was STR was unhappy with his photo-shoot with Karthiga and wanted Tamannaah as the female lead instead. Owing to this and other issues, Simbu infamously dropped out of Ko 3 days before the film's shooting could begin and was replaced by Jiiva within this short period. 

8. Dhruvanatchathiram 

Dhruva Natchathiram has been a production in process for the last four years and when it initially began in 2016, Anu Immanuel was the female lead. However a change in Vikram's schedule caused her to opt out of the movie to be replaced by Ritu Varma.

9. Endhiran 

Tamil cinema's biggest blockbuster Endhiran was initially filmed with Kamal Haasan and Preity Zinta in 2001. The film didn't progress then after photo shoot citing the need for bigger budget and better technologies. Enthiran later came to fruition in 2010 with Rajinikanth and Aishwarya Rai Bachchan.