They took to Facebook to ask whether Chummy, her husband Peter (Ben Caplan) and son Freddie would stop by to see their old friends.
Chummy left the series after season four, and she was known to have been one of the funniest and kindest midwives of all.
Her final episode was the season four finale, which saw Chummy say goodbye to her mother, who was dying.
Actress Hart was due to star in the season five finale, but she was unavailable as she was filming for another project.
Viewers would love to see her return, with one saying: “Maybe Chummy could come back for a visit?”
Another said: “I’d like to see Chummy come back, at least for a visit. I’d also like to see Tom return…maybe rekindle his old romance with Trixie. Mostly, I am just happy the show is returning!”