While Thambikku Endha Ooru helped Rajnikanth test the waters with the comedy-action persona that he has since used to great success, it was his mentor K.Balachander's Thillu Mullu that first explored his comic side. Having graduated from villain to hero, Rajnikanth had been starring in predominantly masala, action movies until then. Thillu Mullu, a remake of Hrishikesh Mukerjee's Golmaal, places him in a purely comic venture with no inkling of stunts or heroisms. It is a clean, enjoyable comedy flick that still succeeds in making us laugh.

Apart from being a hit and thereby opening up a new direction for Rajnikanth professionally, Thillu Mullu was also a landmark movie for Rajnikanth personally. It was during the shooting for this movie that he met college student Latha, who would become Mrs.Latha Rajnikanth the very next year.

Chandran(Rajnikanth) is a playful youngster, intent on having fun with his group of like-minded friends. With advice from a family friend, he poses as a devout, patriotic and simple man with good morals to get a job at the company owned by Sri Ramachandramoorthy('Thengai' Srinivasan). But when his boss spots him at a football match, to which he had gone by lying about an injury to a non-existent mother, Chandran invents a younger brother Indran to solve the predicament. Chandran removes his moustache to become Indran and in that guise, falls in love with Sarojini(Madhavi), Ramachandramoorthy's daughter, while continuing to impress his boss as Chandran.

The movie is good, clean fun with absolutely no crude, vulgar or even slightly uncomfortable moments. As Rajnikanth and then KB proclaim at the beginning, making the viewers laugh is their only motive and they succeed very well at this. And the fun doesn't start just with the double identity scenes. 'Thengai's put-downs and rejection of the first few candidates and the way Rajnikanth impresses him by stressing the characteristics he likes are scenes that are loaded with laughs.

'Thengai' Srinivasan and Sowcar portray two memorable characters and their performances are the strengths of the movie. 'Thengai's expressions and dialog delivery bring to life the stern and policy-strong rich man and his confusion and anger when he sees Rajnikanth and later, Sowcar Janaki, in different settings are hilarious. Sowcar has always been at her comic best in KB's movies(like Bama Vijayam) and steals the scenes she appears in here too. Her innocence when she answers Thengai's pointed queries(like her answer to what Gandhiji did when he came to their house) is appealing and naturally funny.

The same person managing two identities is naturally the crux of the movie and these scenes generate the most laughs. Rajnikanth's audacity with Thengai as Indran contrasts nicely with his show of respect as Chandran. The first scene where he addresses Thengai as the gardener while fully knowing who he is brings out his funny side well. His exasperation as he successively irritates Madhavi(as Chandran) and then romances her(as Indran) is well brought out. The climax is loud and chaotic with the obviously fake backgrounds used in the chase standing out. But the final scene is a very nice touch and serves to perfectly close out the movie.

Rajnikanth displays admirable comic flair when struggling between his two guises. Madhavi is sidelined in the chaos and has nothing much to do. Balachander uses his goodwill and clout in the industry and the movie features a huge bevy of famous actors and actresses like Nagesh, Lakshmi, Y.Vijaya, Pratap Pothan, Visu and the biggest of 'em all, Kamalhassan, in cameo appearances (this could well be the last tamil movie in which Rajnikanth and Kamalhassan appeared together). M.S.Viswanathan tunes a melodious Raagangal Padhinaaru... while the title song provides a catchy and appropriate background score at many points.