Actor Ravi Khanna, who essayed the role of the ISI boss who frames Salman Khan's character as an Indian spy in 'Bajrangi Bhaijaan', says there's a vacuum for an onscreen villain in Bollywood, and feels he can fill it with his authoritative voice and effective screen presence.

'Bajrangi Bhaijaan' reconnected Khanna with Bollywood, who, after 33 years in the US, had moved last year to Mumbai. Now he is exploring new roles, while also working on a book titled "Indian Antagonist", in which he traces the history of the Bollywood villain.