The actress, who plays Cora, Countess of Grantham in the Julian Fellowes' ITV1 period drama, said that the first series was more to her taste.
'There is a slightly different tone to the second season, partly because the show had to deal with this huge elephant which is the First World War, and in some ways Downton Abbey wasn't set up for that,' she told The LA Times.
'What's made the show successful and different is that attention to character detail and that's what the audience likes.
Writers [in the second season] had to do a lot of glossing over the domestic life. Some of the small moments between characters that characterised the first season.'
Find out more