Gena Rowlands, who famously played Allie in “The Notebook,” is dead … TMZ has learned.

The retired actress died Wednesday afternoon at her home in Indian Wells, CA … where she was surrounded by family, including her husband, Robert, and her daughter Alexandra Cassavetes.

We’re told her son, director Nick Cassavetes, had also been at the home frequently this week.

As we reported, Nick announced Gena’s diagnosis back in June … on the 20th anniversary of “The Notebook,” which he directed. Gena’s character in the flick also suffered with the disease.

At the time, Nick said Gena had actually been battling Alzheimer’s for 5 years, and was in “full dementia.”

Gena — the daughter of actress Lady Rowlands, who was also diagnosed with Alzheimer’s before her death — retired from Hollywood in 2015 after earning 4 Emmy awards, 2 Golden Globes, and 2 Oscar nominations.

She collaborated with her first husband, filmmaker John Cassavetes, on a number of occasions … including “Gloria” and “A Woman Under the Influence.”

Gena is survived by Robert — to whom she’s been married since 2012 — and her 3 children … Nick, Alexandra and Zoe Cassavetes.

She was 94.