Joanne played Anna Bates, the personal maid to Lady Mary, in ITV's upstairs downstairs-style drama.
Joanne posted a portrait of the main cast from the show to promote the streaming serviceband captioned the post: "It's not all family fortunes and afternoon tea. Don't miss #DowntonAbbey, streaming on @peacocktv July 15."
It seems that many of the actress' followers were thrilled with the Downton throwback, and took the opportunity to comment underneath the post to share their love for the show.
One person wrote: "I only watched it for the first time in November, I'm now in love with it."
A second person wrote: "Watching the whole series on ITV 3 week nights... I forget how many times I have watched the whole thing, but still love it... we are up to series four, episode eight this evening."
Meanwhile the Liar star has been keeping busy during lockdown with her new podcast which was released last week.
Joanne lends her voice as the lead Jackie O'Hara in a new audio series The Harrowing. The podcast series is a supernatural thriller and tells the story of the devastating events that occur on the Isle of Toll Mòr over five days between Holy Wednesday and Easter Sunday, as recounted by the only survivor – Sergeant O'Hara, played by Laura.