The Singing Hitman! (2010)

A proficient hit man has the necessary skills, but nonetheless has a weakness, which is none other than succumbing to the pleasures of female flesh. Spending a night with a woman, he is tricked and fed a special drug that gives one a heart attack should the person be in a prolonged tense situation. Needing the tension to be able kill the hit man has two choices: find an antidote or sing and dance at least while he awaits for the former. He has a job to do and needs to get on with it.