09/15/2011 02:56 pm ET | Updated Nov 15, 2011

Mitch Winehouse: Amy's Surprising Addiction

Today would've been Amy Winehouse's 28th birthday. Now, nearly two months following the troubled singer's untimely death, her father is opening up about his daughter's health.

Mitch Winehouse, Amy's father, said Amy hadn't touched drugs in nearly three years, but she had replaced a former addiction with new ones.

"Unfortunately, the alcohol, as you may be aware, one addiction can follow another, and this is what happened with Amy," he told CNN's Piers Morgan on Tuesday. In the absence of drugs to get her high, Winehouse had become addicted to exercise.