Cate, 44, beat Meryl Streep (August: Osage County), Sandra Bullock (Gravity), Judi Dench (Philomena) and Emma Thompson (Saving Mr Banks).
The actress looked stunning in a blush-coloured full-length gown but it was her acceptance speech that got everyone talking.
“For those who voted for me, I thank you, and for those who didn’t, better luck next time,” she said, deadpan, before being cut off by the teleprompter telling her she was out of time.
“Twenty-nine seconds? Matthew McConaughey spoke about Neptune and I think I can have five seconds!” she joked, to raucous applause.
Cate is hot favourite to win the best actress Oscar in March, after her performance in Woody Allen’s Blue Jasmine won her the Golden Globe, the Critics’ Choice and the Screen Actors Guild awards.