The 3 tigers in the scene where they corner Vivek Oberoi and John Abraham against the jeep are the same tigers used in the movie Gladiator (2000).
Karan Johar claims he was inspired to do a thriller instead of his usual family film by Aditya Chopra, who had broken Yash Raj Films out of their romantic film mold by doing the action film Dhoom! - Die Jagd beginnt (2004). He paid tribute to Chopra by casting that film's stars, John Abraham and Esha Deol.
Ajay Devgan had a fight on set with Shah Rukh Khan over his wife Kajol.
Lead Actor Ajay Devgn 3rd villanous role in Kaal after successful movie like Deewangee(2002)& Khakee(2004).
Sanjay Dutt , Nana Patekar , Saif Ali Khan , Shahid Kapoor , Priyanka Chopra & Kajol ; these all were replaced by the Ajay Devgn , John Abraham , Vivek Oberoi , Esha Deol & Lara Dutta in the film.