"There were no apprehensions. Actors who play romantic heroes in most of the films don't get apprehensive before taking another such project; so why should I?" he said.
Directed by Sangeeth Sivan, "Ek" is a remake of Telugu film "Athadu" and also stars southern star Shriya Saran.
"Though I also did such a role in 'Bichhoo', this one is a far more stylised version of a professional killer. In fact I was very excited when I saw the southern version of 'Ek' and said yes to the role, " Bobby told over phone from Mumbai.
Known for his action image, the 39-year-old said that the action sequences in the film were something to look out for.
"The USP of the film is its action. It has been shot and choreographed very well and it will offer amazing action sequences to all action fans in the country. They'll love it, " he said.
Bobby shrugged off media rumours that he jumped of the 14th floor for the film.
"My jump has been exaggerated in the media. I jumped only from the seventh floor, not 14th - though that was also scary enough, " he laughed.
Bobby, who was last seen in "Dostana" with short cropped hair, was excited about his new look in "Ek".
"I sport a straightened hair look in the film. It's ironic that my hair has been straightened despite my constant advice to people that one should not get them straightened at all as it spoils your hair, " the actor said.
The film has Nana Patekar playing a Central Bureau of Investigation (CBI) inspector and Bobby is all praise for the 58- year-old's energy levels.
"Nana is a great guy. He is so agile and active. In fact, for his age, he is so fit and I really admire him for that, " he said.
Apparently Nana almost always surprised the unit members with his energetic sprints and his rigorous gym sessions.
But Bobby too is known for his fit physique. What's the secret behind that?
"As far as my physical regime is concerned, I just do my usual workout including a bit of cardio. I don't work very specifically on my body for any one film, " the actor said.
Asked if he also planned to venture into direction like his elder brother Sunny, he said: "I don't know. I can't foresee the future. It's a dream of every actor to direct a film some day, but who knows."
Bobby's future projects include "Cheers - Celebrate Life", "Roshan", "Formula No.44" and "Gangs of London".