She firstly made a cameo appearance during the night of Friday April 12th during Dinner, sometime before Rose leaves and tries to commit suicide. On Saturday April 13th, she is seen socializing with Ruth DeWitt Bukater and another lady during Afternoon Tea, and trying to avoid the company of Margaret Brown, who nonetheless decided to walk with them.
Sometime later, the ladies found Rose DeWitt Bukater and Jack Dawson spitting. Later she was seen sometime before the dinner with Cal and Ruth. Some seconds later she is with Captain Smith in the First Class dinner room and sits next to Jack during the dinner.
When the dinner finishes she talks with Ruth and Lucile Duff-Gordon. She appears again during the prayer services, and later with Ruth, Lucile and Rose during the final evening in the 1st-Class Lounge for Afternoon Tea talking about Rose's wedding.
The Countess appears again a few minutes after the collision with the iceberg and asks a Steward 1 why the engines had stopped. The Steward replies that it was probably a dropped propeller blade and offers to bring her something. She politely refuses when she sees Thomas Andrews walking past with blueprints looking very serious. She assumes nothing is wrong and goes back to sleep.
This is the only time she ever talks in the film. She escaped to lifeboat 8. During her survival on lifeboat 8 she generously helped the third class passengers on this boat and later the rest of the third class passengers. These all events are unseen in the film. She lastly appears on the Carpathia deck after her survival.
- Noël Leslie, Countess of Rothes on Wikipedia