Focus Features is previewing Downton Abbey: The Grand Finale.
Smith, who was also well-known for her role as Professor McGonagall in the Harry Potter film series, died in September. She was 89 years old.
Hugh Bonneville, who portrays Violet's son Robert in Downton Abbey, described Smith as "a true legend of her generation."
"Anyone who ever shared a scene with Maggie will attest to her sharp eye, sharp wit and formidable talent," he said at the time.
Bonneville is among the many cast members returning for the third Downton Abbey film. Downton Abbey opened in theaters in 2019, while Downton Abbey: A New Era arrived in 2022. The movies serve as sequels to the ITV series.Other returning stars include Elizabeth McGovern, Laura Carmichael, Jim Carter, Phyllis Logan, Robert James-Collier, Joanne Froggatt, Allen Leech, Penelope Wilton, Lesley Nichol, Michael Fox, Raquel Cassidy, Brendan Coyle, Kevin Doyle, Harry Hadden-Paton, Sophie McShera, Douglas Reith and Dominic West.
Paul Giamatti, Joely Richardson, Alessandro Nivola, Simon Russell Beale and Arty Frouhshan join the cast in the upcoming film.
