According to his death certificate, the lead singer of the heavy metal band Motorhead died from prostate cancer and congestive heart failure, reported Us magazine.
When the musician, who was 70, died in December, it was revealed that he battled an "extremely aggressive" cancer for a short time.
A statement from the band's Facebook page revealed that Kilmister only received the cancer diagnosis two days before he died.
While he was unaware of the cancer until recently, Kilmister dealt with significant health issues for a while, which eventually forced him to decrease his alcohol and tobacco intake, after 57 years of smoking.