Bollywood is known to bat for the underdog and often one with certain mental disabilities as we saw Hrithik Roshan in "Koi Mil Gaya" and Anil Kapoor in "Yuvvraaj". And now superstar Shah Rukh Khan will explore yet another illness plaguing the human mind in "My Name Is Khan".

Directed by Karan Johar and co-produced by his Dharma Productions and Shah Rukh's Red Chillies Entertainment, "My Name Is Khan" is about Rizwan Khan, a man with Asperger syndrome, who is mistaken for a terrorist while travelling in the US.

Asperger syndrome is a kind of autism and people affected by it show significant difficulties in social interaction, along with restricted and repetitive patterns of behaviour and interests.

"Shah Rukh has done monumental research on his autistic character. I was zapped by how much he knew on the subject. And he brought all the knowledge on the sets. He had written reams of notes on how he wanted to interpret his character, " Johar had told IANS in an interview.

The film that also stars Kajol in a key role will hit theatres Feb 12.

This is not the first time a mainstream star is playing such a role.

Anil Kapoor played a 'mentally slow' man in director K. Vishwanath's critically acclaimed "Eeshwar" (1989). The film was about a man who is fully grown but still acts like a child. He is mentally unstable, but is a gifted singer and fulfils his responsibilities after marrying a widow who is left with a child.

And in 2008, the 50-year-old actor yet again impressed both critics and fans by playing a similar role in Subhash Ghai's "Yuvvraaj". Anil essayed a character who suffered from autism but was a musical genius in the multi-starrer drama.

Bollywood heartthrob Hrithik Roshan too played a character suffering from a mental illness in dad Rakesh Roshan's "Koi...Mil Gaya". The film revolved around a developmentally disabled young man who tries to complete his father's research on communicating with extra terrestrials from outer space.

"My character Rohit isn't autistic. He's born with a deficient part in his brain. He's mentally 10 years behind other people his age, " Hrithik had said around the release of the film in 2003.

"Unlike other actors playing mentally challenged characters, I had to make Rohit look smart. He's always playing pranks on guys twice his age and size, " the star said.

In 2005 release "Main Aisa Hi Hoon", Ajay Devgn was seen as a mentally-challenged man fighting for the custody of his daughter. It also starred Sushmita Sen, Eesha Deol and Anupam Kher.

Even actresses haven't shied away from doing such intense roles.

Dia Mirza played a mentally challenged girl Nazeen in Khalid Mohammad's "Tehzeeb". The film also featured Urmila Matondkar, Shabana Azmi and Arjun Rampal.

In 1983, Sridevi starred opposite Kamal Haasan in the drama "Sadma". In the film, Sridevi brilliantly portrayed the character of a young woman who regresses to childhood after suffering a head injury in a car crash. It fetched Sridevi her first Filmfare nomination for best actress.