He also collaborated as a writer for US television documentary Terrorism: Bio Attack (2005).
His acting debut was in the poorly received 2005 film called Fun: Can Be Dangerous Sometimes.
A more serious role was his second venture in the critically acclaimed Anwar (2007), which also did poorly at the box office.
Siddharth took a long break and made a comeback in the directorial debut of Pakistani actor Rahat Kazmi, the dark comedy film Dekh Bhai Dekh (2009), which opened to mild response.
He was seen then in a film about the 26 November 2008 Mumbai attacks, entitled Deshdrohi 2, directed by Kamaal R. Khan in 2009.