Heath Ledger's dad talks about how his granddaughter is keeping his son's legacy alive.

Kim Ledger is now campaigning to raise awareness of the dangers of prescription drugs.

It’s been seven years since Heath Ledger died. And now in an interview, his father has spoken about his son and reflected on the life he lead.

Kim Ledger appeared on The Project and talked about the late actor’s family, including Heath’s daughter, Matilda. “She’s got an enormous number of his mannerisms. She’s very inquisitive, she’s got his energy… ’cause Heath never slept from when he was two and Matilda’s like that,” Kim said.

“She’s always full of questions, always wanting to know this or that about her dad. And I guess that will just get more intense as she gets older and obviously we would welcome that,” he continued.

“I mean, she’s just got this ball of energy and she radiates this little aura, Heath was kind of like that. So it’s fabulous really.”

Related: Accidental addicts: Prescription medications are killing more Aussies than illicit drugs.

Kim also spoke about actress Michelle Williams, Matilda’s mother.

“Michelle’s been brilliant. She’s kept Heath very much alive in her daughter’s eyes.”

In the seven years since his son’s untimely death, Kim has been campaigning for more awareness regarding the dangers of prescription drugs.

“I made this organisation because I was approached by families that were in the same situation that we were, that we found ourselves in accidentally,” he said.

“I think it’s lack of education, at the end of the day I guess there’s a feeling out there that if the doctor prescribes it, it’s okay. If you’re not across the type of effect that mixing these drugs can have obviously it can have a very detrimental effect.”

Related: The anti-depressant side effect that nobody talks about.

Perhaps the hardest part of the interview was when Kim was painfully honest about his son’s last days. Travel, stress and illness all contributed to his final moments.

“In Heath’s particular case, he was having to travel a lot between Vancouver, London, New York – all within the space of a short time. He was also suffering a bad chest infection and he couldn’t sleep as a result of that,” he said.

“He’s called into a couple of doctors, complained about his problem, he has a reasonable profile, they don’t question anything and he’s taken a mixture of these drugs and then on top of that a sleeping tablet and he’s gone to sleep.”

You can see the full video by clicking here.