– Actress Michelle Dockery finds herself intimidated by every new role.

"I feel like I know I can do it, and I see myself doing it, but there is this fear of being bad or failing," she said. "I think all actors have it. It's what makes us nervous and sometimes a bit neurotic.

"You just want to be truthful and real. And I never think I'm going to be brilliant in anything. It's not self-doubt as such, it's just a very natural thing in an actor — a natural feeling of not being believable."

When she first read the role of the aloof Lady Mary in "Downton Abbey," Dockery was scared. "I read that part and thought, 'I want this part so much!' It's rare, actually, that a part comes along and you really believe that this is the part for you. I have that thing where I'm like, 'Oh, I'm sure they'll probably go with someone younger, or they'll go for someone older. I like the part but. … '

"Then every now and then, something comes up and you think, 'This is mine. I know this character. I want to play this character!' That's how I felt about Mary. But at the same time she's a character — I'm from a com-plete-ly different background. The accent was something I had to really work on. It was a challenge, and it still is."

How she rose to the challenge has become part of television history as "Downton Abbey" became one of the most popular dramas ever to grace the tube. And Dockery's pale and contained Lady Mary crystallized an unparalleled cast performance and earned her three Emmy nominations.

When Dockery auditioned for the part, the producer of "Downton" had seen her play the guttersnipe Eliza Doolittle in "Pygmalion," a character eons away from the upper-crusty Lady Mary Crawley.

"I thought of her as a young Kristin Scott Thomas, like the role she played in 'Gosford Park,' " said Dockery, dressed in a sleeveless white chiffon dress and black ballet flats.

"She's the young, haughty aristocrat. So I got the character straightaway. I walked away [from the audition] thinking they'll probably give it to a really well known actress. At the time there were a lot of actresses who were doing loads of period drama in films. I just thought, 'Oh, someone's definitely going to want to do this role.' "

She knew by the end of the day that she had been cast. "But I never knew it would change my life the way it did," she said.

Shy by nature, Dockery wasn't prepared for the media blitz that followed. "The fame that comes sometimes can be overwhelming," she said, sighing. "Even the first year of 'Downton.'

"It aired, and the following Sunday the three [Crawley] sisters were on the cover of three newspapers in my local news agents. I couldn't believe it. Of course, it's exciting and it's thrilling, but then suddenly you're not anonymous anymore. That was a big adjustment for me because I'm very shy among big groups of people. I can be better in just a one-to-one — that was an adjustment, really, for me."

She said there's no way to prepare for an eruption like that. "But it's having good people around you who know who you are in spite of all that, they know who you were before," she said. "It's the people who knew you before that happened, they're the ones to cling to."

For her, that means her family and her sweetheart, John Dineen, who works in financial publicity. They were introduced a year ago last May by actor Allen Leech, who plays Tom Branson on the show. And while she's reluctant to discuss him, she said meeting Dineen changed her life.

The woman who toiled as a waitress in a fish-and-chip cafe, served as a barmaid and as a recruitment temp for the Times and later fumbled orders in an Italian restaurant recalls that drama school was expensive, and that she had to do what she could to earn a living. "There were times I couldn't quite make my rent, but I'd always find a way of earning money here and there," she said.

"My family are very hard workers. My dad, he was up and out of the house at 7 o'clock during the day. He did all sorts of jobs when I was growing up, a lot of driving jobs. … He did a lot of delivery work. I remember when I was off sick from school, going off with my dad in his van. Then he got his degree in his 50s as an environmental chemist so he's a surveyor now and he's been doing that since I was 14 or 15. I actually find it very easy to get out of bed in the morning — I think that's from my dad."

Dockery, 33, also feels that the notoriety of the series has helped her.

"I kind of grew in confidence with 'Downton,' " she said. "Publicity and the red carpets — I just didn't want to do it. … I remember going on the Letterman show and being so terrified and then actually watching it back and thinking, 'Oh, I'm doing all right, actually.' That was the tipping point for me, knowing what I was capable of, that I could do it."

She's also thrilled that she's had a steady job for five years. "That's a blessing to know six months ahead you're going to be employed. That is a lovely feeling, and having some financial stability. Before 'Downton' I was living in a tiny, little flat with a girl I didn't really know in East London. Now I have a place of my own. And there are such privileges that come with it."