Siobhan Finneran has revealed that she identifies with her villainous Downton Abbey character O'Brien.
The first two series of Downton Abbey have seen the maid O'Brien masterminding a series of increasingly dangerous schemes, but Finneran told ET Online that she's tried hard to bring humanity to the character.
"I really, really like her so that helps a great amount and I find her very funny and a little bit naughty," the actress said. "I think when we first saw her, everyone assumed she would be Cruella De Vil or the Wicked Witch of the West - but there's so much more going on beneath that."
She continued: "I think sometimes her severity and the way she is with the other people in the house comes down to the fact that she's completely brilliant at her job and will never let anything take that away from her.
"She doesn't like to be out of control and is more aware of everybody in the house more than anybody else is. And I think that comes from some dark, dim past which we don't ever find out about - which I quite like because I think it keeps the audience guessing as to why she behaves the way she does."
Finneran - who has previously starred in Clocking Off and Wire in the Blood - also commented on why she believes Downton Abbey has become an international hit.
"I think we all quite like seeing into other people's homes. In the time it came out, there was very little set in that time and people love a period drama," she explained. "Also, I think the way Julian [Fellowes] wrote the characters, there's something about each character that appeals to the audience.
"Whether they recognise a part of themselves in that character, or just empathise with them - once you can do that, you're really invested in whatever journey those people are going on so they can see who's doing what, to who, and when."
It was announced this week that Shirley MacLaine will join Downton Abbey as Lady Grantham's mother for the third series.
Downton Abbey is currently airing in the US on Sundays at 9pm EST on PBS.