Paul Bettany took drugs to help numb the pain of his brother's death.
The 'Avengers: Age of Ultron' star's younger sibling Matthew died aged eight after fracturing his skull in a freak accident when Paul was 16 and he has confessed he turned to alcohol and cocaine decades later to help him come to terms with his passing.
After leaving home and working as a street busker in the years after his brother's death, the 44-year-old actor finally landed his breakthrough movie role in 'A Knight's Tale' in 2001, but became heavily dependent on the substances.
He recalled: "[It was] manic. I don't know if I was aware I was numbing myself at the time. I don't think [there was anger]. It was nobody's fault. It was the awfulness that is bad luck. Had there not been a heavy dew that morning."
Paul - who has two children Stellan, 11, and Agnes, three, with his wife Jennifer Connelly - added the accident still impacts on his daily life and has caused him to feel increasingly anxious following the birth of his children.
In an interview with The Times newspaper, he said: "I think (the accident) is the very centre of my feeling that life is precarious, but I think I'm becoming better at it. As more years pass without another catastrophe, I realise that the worst-case scenario often doesn't happen.
"I am definitely feeling calmer on that but don't think it will ever entirely leave. It's an indelible worry."