Hawaii Five-0 actor Alex O'Loughlin has overhauled his health and diet following his stint in rehab last year (12).

The Australian star checked himself into a clinic to receive professional help to beat his addiction to painkillers after getting hooked on the pills following a shoulder injury.

He took time off from the show to focus on his recovery and has adopted the strict Paleolithic eating regime, which restricts followers to the diet of early humans.

He tells Australia's Sydney Morning Herald, "I feel really good; I've made a few dietary changes and I'm exploring the whole Paleo thing and training hard, so I'm feeling good."