Rani Mukerji had interactive sessions with author Brad Cohen, on whose autobiography her film Hichki is 
based, to learn about the Tourette syndrome. 

The actress’s story in the film, directed by Siddharth P. Malhotra, mirrors the life of Cohen, a motivational speaker and teacher from the United States. He had written Front of the Class : How Tourette Syndrome Made Me the Teacher I 
Never Had.

Hichki features Rani as Naina Mathur, an inspiring and self-motivated school teacher who suffers from Tourrete syndrome. Malhotra said he had been in constant touch with Cohen on the film for five years and narrated the project to Rani in 2016. 

“... I’ve been tic-ing (rapid movements or sounds repeated for no reason, beyond the control of a person with Tourette syndrome) throughout those five years in his voice and giving those narrations. So when I narrated the script to her I narrated it with the tics.. Even to Adi (Chopra) and Maneesh (Sharma) I narrated it with the tics. So we knew that’s a tough one to come around. So made her (Rani) meet some people with Tourettes,” he said. 

Rani interacted with Cohen over Skype to understand the character better. “Brad almost did one week to two weeks of back and forth communications with Rani and almost for an hour each session... Showed her how he gets excited to the fact that he tics it every 2 or 3 seconds and the fact that he tries to calm himself down. 

“So after understanding what Brad could do she internalised him. And that’s when she came up with her own tics and that is how she became Brad. That’s when she came back, she called me and said this is what I’m planning to do. We improvised a bit, read a few lines, a few scenes with the tics,” Malhotra added. 

Cohen will promote the film from the US. A source from the production house said: “Brad will promote Hichki from the US. He has been excited about the film being made in Hindi and his best wishes are with Rani and the entire team. Brad loves the trailer and wants to lend his support to spread awareness around Tourette syndrome in India and the world over.”