Downton Abbey star Laura Carmichael says she had no idea she would be playing the "ugly" Crawley sister until she first read a review of the hit ITV show.

"It was really funny opening the newspaper and reading the reviews and going, 'Oh, I'm playing the ugly one' - I hadn't thought about that!" the 28-year-old actress told the Radio Times. 

Carmichael was cast as the straight-talking Lady Edith alongside her on-screen sisters Lady Mary (played by Michelle Dockery) and Lady Sybil (Jessica Brown Findlay) in 2010, when the award-winning show first hit our screens.

The period drama is now in its fifth season and Carmichael says the perception of Lady Mary as the beautiful sister means she and Dockery still get treated differently, even off screen.

"We definitely have a different way. I’ve watched people talk to Michelle like she’s the queen – she’s Lady Mary," she said. 

Carmichael says members of the public also approach her in a certain way as a result of her status as an "upstairs" character.

"People ask me to go horse-riding and things. I have to say, ‘I’m not really posh, I don’t own a horse, I don’t know how to do it,'" she said. "And with Jim [Carter, who plays Carson the butler] they’re more matey. It’s weird.

"I sometimes feel people are disappointed when they see you in jeans. You’ve spoilt their fiction slightly," she went on. 

Carmichael hinted that Downton Abbey may come to an end while it is still riding on a high with viewers.

Referring to the show's creator Julian Fellowes, she said,  "I know it’s his intention to write until the point that seems right [to stop]. It won’t be on forever."  

She added, "I say that, what do I know, I don’t know, I really don’t know! But I don’t think that’s his ambition."

It comes as Hugh Bonneville, who plays the Earl of Grantham, last month pointed out that Fellowes would want to "quit while he's ahead".

Carmichael hails from Southampton and studied at the Old Vic Theatre before she was asked to read for a role in Downton.

Her subsequent portrayal of Lady Edith has seen her career flourish, with a cover shoot on Vogue and a part in the West End drama Uncle Vanya at the Vaudeville Theatre in 2012. 

Historically, her character Lady Edith had a tough time of it on the show - she's been overshadowed by her sisters, dismissed by her other relatives and left abandoned at the hands of a vanishing lover.

"Julian [Fellowes] has a theory that some people in life are lucky and some people are not. And Edith has not been lucky," Carmichael  told Hitflix earlier this year. "But I think, to her credit, it's helped her be a far more proactive person and the sort of a modern day woman in that way, because she hasn't laid down and let it all washed over her. She has gotten up and gone to work and created a life for herself."