Hundreds of audience gathered to catch a glimpse of their favourite stars at an event in Mumbai.
Khan and Kapoor enticed the audience and distributed the film's merchandise such as tennis caps.
"I think she has been one of the biggest strengths in the film," said Khan.
Khan was all praise for the child actor Armaan Verma who essays the role of his son, Prateek Subramanium in the movie.
The story of Ra One revolves around Khan, who plays the lead protagonist, turning into a superhero in order to fulfill his son's expectations.
The movie takes a turn when Khan's character designs a videogame that has an impact on the lives of the characters, in both negative and positive ways.
Besides Khan and Kapoor, actors Dalip Tahil, Satish Shah and Shahana Goswami also essay key roles in the thrilling movie.
The music of the film is composed by musician duo Vishal-Shekhar.
The action-packed science-fiction film, directed by Anubhav Sinha, is slated for October 26 release. (Reuters)
