Michelle Dockery says some of the period costumes used in 'Downton Abbey' are ''falling to pieces''.

The 30-year-old actress - who plays Lady Mary Crawley in the drama series - revealed producers are determined to use original pieces which have been patched up as much as possible to create an authentic feel in the show.

She said: ''Some of them are vintage pieces -- original pieces that have been revamped.''

The brunette beauty admitted the cast wear historically accurate items right down to their underwear, but they also get away with wearing more modern garments, such as Ugg boots underneath their long period dresses, when the weather takes a turn for the worse.

Speaking at a Television Critics Association panel in Beverly Hills, she added: ''The corsets are made for us. And there are things you don't get to see, like the microphone packs that are strapped to our calves and The Wire [that] goes right up.

''When it is raining, we wear Ugg boots underneath our dresses. It's not as glamorous as it may seem.''

US star Elizabeth McGovern - who plays aristocratic Lady Grantham in 'Downton' - recently admitted it is ''very hard work'' wearing a tight-fitting corset on set all day.

She said: ''They put you in a corset and, baby, they Squeeze that tight! At the end of the day my intestines are in my throat and in my legs! It's very hard work.

''I enjoy wearing them but it's nice to leave them at work.''