Froggatt and her husband, James Cannon, are set to spend six months living in Los Angeles after she finishes filming the next series of Downton Abbey. Her assault on Hollywood may come even though she senses she may not fit in.
"I'm not a big-budget Hollywood type. They want the model type, classically beautiful, and I'm not," she said.
Asked whether this was due to sexism, she said that there were more interesting character roles for men.
"Also there are more actresses than actors so there is more competition. But things are getting better for women, particularly on TV."
Her plain-looking character in Downton Abbey has been raped and accused of murder and is far from the glamour of Hollywood.
"The weird thing is that I wouldn't leave the house like that on a day-to-day basis. I don't go to the gym without mascara and foundation on, and yet I'm quite happy for millions of people to see me looking absolutely terrible on screen.
"I don't have any vanity when I'm acting as long as it's right for the role. It just so happens that Anna Bates in Downton or my film roles have not been very glamorous."
The second half of the Downton Abbey Christmas Special screens on Prime, Thursday 8.30pm.
- AAP