Kelsey Grammer became addicted to drugs as he couldn't "forgive" himself for sister's death

Speaking of his abuse of alcohol and cocaine in the late 1980s and 1990s, he said: "I'll speak to the straight of it. That was the time when I could not forgive myself for my sister's death."

In a 2009 letter opposing killer Freddie Glenn's parole, Kelsey spoke of how he wished he could have "protected" his sister as he felt was his duty as her "big brother", and he admits now his viewpoint was "not rational".

Asked how he could have protected Karen even though they didn't live in the same state, he told the new issue of Vanity Fair magazine: "It's hard to explain. It's not rational. But it happens anyway. I know a lot of people who've lost their siblings and blame themselves."

The 60-year-old actor has also coped with his estranged father being murdered by a psychopath and his two half-brothers dying in a scuba-diving accident and he now views tragedy as just a "part of life".

He said: "Every one of us is going to experience some terrible loss. I just got a big dose. For every story you hear that's tragic, there's another that's equally tragic or more so. I think you come to look at it as part of life."

These days, Kelsey is incredibly happy thanks to fourth wife Kayte Walsh and their children Faith, two, and Kelsey Jr, eight months.

The actor - who has four other children from previous relationships - said: "This lovely young woman lit up my world and changed my heart, which was a bit calloused and hardened against a lot of things. And we are good, and I feel young and alive."