Meryl Streep has revealed that she wanted to show the "human being" behind Margaret Thatcher's fearsome reputation.
The Oscar-winning actress plays the former British Prime Minister in controversial biopic The Iron Lady which premiered at the BFI in London.
Streep said: "I consider all the roles I play a privilege but this one was special because there are such vehement opinions about her.
"People seemed to look at her as an icon or a monster and I just wanted to locate the human being inside those caricatures that we've seen over so many years. And to investigate myself what it must have been like for her."
Many fans braved the wind and rain to greet Streep and fellow stars of the film Jim Broadbent, Olivia Colman, Richard E Grant and Anthony Head on the red carpet.
Mamma Mia's Phyllida Lloyd has directed the moving story written by The Hour's Abi Morgan, which sees the former leader, lonely and senile, looking back on her life and imagining her late husband Denis Thatcher, played by Broadbent, is still with her.
Streep has been tipped for an Oscar nomination for the role, which could lead to her third win.
She said: "It would be great, because the secret of the nomination is that it comes from the actors and actors are the ones who know what you go through. So it would be amazing."
The Thatcher family declined an invitation to see the film.
Director Lloyd said: "We invited them to see the film when we'd just completed it and they didn't come to see it at that time, which I quite understand. They probably want to watch it in the privacy of their own home."