An autopsy performed on The Monkees star Davy Jones has confirmed he died of a severe heart attack.

The British-born singer/actor passed away in Florida on Wednesday at the age of 66.

The Martin County Medical Examiner conducted the post-mortem examination on Thursday morning and ruled that Jones had died from an abnormal heart rhythm caused by a coronary artery atherosclerosis, reports TMZ.com.

The coroner has also carried out toxicology tests to back up the findings, and the results are pending.

Jones' The Monkees bandmate Micky Dolenz admitted on Wednesday that news of his old pal's death came as a shock as the frontman was the youngest and healthiest of the group.

Dolenz told CNN's Piers Morgan, "(I'm in) total shock. I thought he would have been the last of us (to die). He was the youngest of us... I thought it would have been me (to die first), I'm not a vegetarian... I'm bewildered."