While Maggie, 88, will no doubt miss reuniting with her dear colleagues, she has previously said that the Dowager Countess' number was up.
"By the time we're through - she must've been 110," Maggie said about the series finale.
"So, I couldn't go on and on and on. I couldn't. It just didn't make sense."
WATCH: Highclere Castle with the cast of Downton Abbey
As for what might happen in this new season, there's already been early speculation that it could focus on how the Crawleys manage Downton Abbey during the Great Depression, following the stock market crash of 1929.
Other chatter suggests a significant time jump could be involved, with the action taking place during World War II from 1939 to 1945.
For more, pick up the latest issue of New Idea!