What would the Dowager say? As Elizabeth McGovern temporarily steps out of the role of the Countess of Grantham to front her band, she admits fans of the hugely popular ITV period drama may find the idea of Lady Cora as a rock chick, a bit odd.
But McGovern believes her own character would have been a fan.
I like to think Lady Cora would be quite into it. She does a have a relatively open mind, compared to her English relatives. She is capable of embracing something new.
The 51-year-old has been singing with Sadie and the Hotheads for the past five years, which McGovern said had given her a sense of freedom.
"I feel a sense of power (singing and songwriting) that I don't feel in the acting profession.
"While acting, I work very hard. It's my job and responsibility to embody someone elses vision.
"In music, I have my own voice coming through. It fills a part of myself that I was increasingly hungry to fill as I got older.
"It's very much a conduit for my own personality. Sadie is me, with a great singing voice."
The bands new album, How Not to Lose Things, features a variety of different genres, from the quirky country and western Cow Song, to the cool jazz of My Debt Collector.
But all tracks are deeply rooted in McGovern's American upbringing.
"It's like a comfort blanket. It's bringing a bit of homeland into my life.
"It makes people uncomfortable sometimes because it doesn't fit into a certain genre.
"I don't understand it, I like music which has variety. We weren't writing for a market, we were just writing for ourselves.
"I never thought it would get so far. It's one of those weird kind of miracles."
But with the tour about to begin, and filming for Downton Abbey series four starting next February, McGovern said she was putting any more songwriting on hold for now.
"I'm stretched in so many directions at the moment. I don't have any more space in my brain.
"Anytime I write a group of songs, it's like giving birth to a child. It's amazing but it has demands on you.
"I'm nursing this group of songs along at the moment."
Sadie and the Hotheads are playing at Birmingham's Adrian Boult Hall on February 8.