She firstly made a cameo during the First Class dinner sometime before Rose leaves and tries to commit suicide. The second day of voyage she socializing with Ruth DeWitt Bukater and another lady, finishing their tea and trying to avoid the company of Margaret Brown, who nonetheless decided to walk with them.
The ladies sometime later 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 with Ruth, Lucile and Rose talking about Rose's wedding with Cal. The Countess appears again some minutes after the crush of the ship with the iceberg and asks a steward what's going on, she refuses when the steward asks her for tea and leaves when anxiously eyes to Thomas Andrews.
This is the only time she ever talk to 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.