Mortimer returned to the screen in 2019 with "Good Posture." It co-stars Grace Van Patten as Lilian, a young woman who moves in with her father's friend, a reclusive novelist called Julia Price (Mortimer). Of her character, she said, "I wish I had just one per cent of Julia’s frostiness in my own life. I really enjoyed being that person, feeling what it’s like to be intimidating." The film was made by Mortimer's friend, Dolly Wells, in her directorial debut. The actor's performance earned praise, but several critics were disappointed with her amount of screen time. Next, she appeared in Greg Kinnear's comedy "Phil"; it was negatively received by critics. In the horror film "Mary", Mortimer starred opposite Gary Oldman. The film is about a family in isolated waters and the ship they bought which has terrifying secrets. "Mary" was panned by critics, and the "Los Angeles Times" thought the actors talents were wasted.