Natalie Portman has said she felt "incredibly lucky" to have been able to play former First Lady, Jacqueline Kennedy Onassis, in Jackie.
The film documents the dramatic events that unfolded for Jackie Kennedy after the assassination of her husband, former American president John F Kennedy.
Natalie, who is nominated for the best actress in a film Golden Globe for her role, said during the event's Twitter live stream: "I was really lucky to get to play the role because she's just an incredible woman, so multi-faceted and there is a lot of material online so I had hours of footage I watched over and over again."
She also said, later on the red carpet, what she was the most surprised to learn about Jackie.
She said: "There are many things, I always knew she was smart but not how smart she was, and certainly didn't realise the role she had in crafting the legacy of her husband and family, and how important image is - it actually corresponds to the substantive understanding of a person."
The actress, who is pregnant with her second child, wore an embellished empire line dress by Prada.
She was joined on the red carpet by husband Benjamin Millepied.