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"Catherine was a serial monogamist and one of her lines was, 'I'm in love with love'," Mirren added.
"She was a woman who always wanted to have a man, but she didn't want to relinquish power. She loved sex and she loves a sexual relationship, but when she wanted to get rid of them after, she'd give them palaces or something.
"She even gave one guy a country, making him King of Poland (Stanislaw August Poniatowski).
"I hate that in history men can sleep with anyone they want but women are punished for their sexuality. There was always the intimation that Catherine was some sort of debauched, mad, sexual creature, but those rumours absolutely weren't true."
Mirren was referring to the wild rumour that has plagued Catherine the Great since her death in 1796 – that she died having sex with a horse.
German-born Catherine became ruler of Russia after deposing her husband, Emperor Peter III, a violent, drunken bully.
Despite her success and smarts, Catherine's sex life was the dominating subject, which historians claim was a way to detract from her powerful leadership, all of which will play out in the series.
Catherine the Great's lust was reportedly so powerful she was enticed to sleep with horses, which led to her death. Legend has it that the leather harness holding the horse above her snapped and Catherine was crushed to death.
While there is no confirmation whether or not this rumour is true, many say it was just the whispers of misogynists attempting to tarnish her extraordinary achievements.
Mirren strongly agrees, telling The Sun: "It's appalling the way history treats successful, powerful women. It has to pull them down. Her unbelievable achievements were very successful, obfuscated by history.
"I have feminist friends who say, 'Oh, what are you going to do about the horse?', which of course is a complete lie, a classic way of belittling her."
It will be interesting to see how the series approaches the subject.