Her husband, Steve Sheen, stated that Quirke first suspected an issue in November 2020 when she struggled to learn lines for a role.
The family initially dismissed the diagnosis, believing it could be long Covid, and expressed surprise at her age, noting a lack of information on dementia's progression.
Quirke's son, Charlie, is undertaking a 140-kilometre charity walk for Alzheimer's Research UK to raise awareness and funds.
The family aims to highlight the importance of dementia awareness, with Pauline Quirke now serving as an Ambassador for Alzheimer's Research UK.