The former Harry Potter actress was awarded the British Artist of the Year award at the annual event when she spoke of how the Harry Potter set decorators built the hamster a miniature coffin.
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Emma Watson accepts the British Artist of the Year award
"I'm especially honoured to be receiving this award... because the British film industry hasn't just been a workplace for me, it's been the place I've grown up, it's been a surrogate family, really", Emma began her speech.
She continued: "And a sweet but slightly morbid example of this, is when on the first Harry Potter film, my on-set hamster, Millie, had a heart attack and didn't quite make it.
"So the set decorators built a small, mahogany-sized hamster coffin. And it had a velvet lining and a silver plaque on the front which had Millie's name engraved on it"
The audience, which included Dame Judi Dench and Robert Downey Jr. laughed warmly at Emma's speech, and the 24-year-old actress added: "Anyway, what I'm trying to say is, you're all very special to me, and your vote of confidence means a lot. And I take it as such a great honour that you're giving me this award tonight.
Honorees Robert Downey Jr., Emma Watson, Dame Judi Dench, Mike Leigh, OBE, Julia Louis-Dreyfus and Mark Ruffalo
"I mean business. Thank you very, very much, and rest in peace, Millie. This one's for you."
The unusual speech follows Emma's much-lauded speech to the UN in September, where she called on men to support their "daughters, sisters and mothers" and to fight for gender equality.
Emma was recently appointed as a UN Goodwill Ambassador for Women, and gave a rousing speech at the UN headquarters in New York.
Emma was launching the HeForShe campaign – a solidarity movement for gender equality that "brings together one half of humanity in support of the other" - and warned against confusing feminism – "an unpopular word" – with "man-hating".