The Queen star was the subject of a Life in Pictures retrospective in London, and she admitted her ambition early in her career was just to be famous.
She says, "To be honest, I just wanted to be a star. As a new actress you have to learn quickly how to behave on set and interact with crew. At the beginning I was in my own bubble."
Mirren also revealed her personal philosophy is "always do the dangerous and slightly radical things", and told the crowd she never thinks about her scenes once she has stepped away from the set.
She added, "Never go home at night and re-do the scene in your head. Drop it and let it go... terrifying as that sounds!"