Diane Keaton was a respected actress — but many don’t know about her side hustle.

Keaton, who died last October of pneumonia at the age of 79, was also a prolific property investor who renovated and flipped homes. One of them, a 1920s Spanish Colonial revival in Beverly Hills, listed for $25 million in the wake of her death — and now it’s available for less.

According to Robb Report, after six months with no deal struck, the property now seeks about $21 million for sale, marking a nearly $5 million discount.

Keaton bought the dwelling for $8.1 million in 2007 from Madonna and, along with her longtime collaborator Stephen Shadley, carried out a loving restoration that made its way to the pages of Architectural Digest. Together, they brought back its architectural character — its charming beamed ceilings, arched doorways and terracotta tiles.

But Keaton also added her own details, such as converting the entry hall into a library, which listing images show comes with floor-to-ceiling shelves. Keaton additionally created a kitchen under a vaulted ceiling anchored by a fireplace.

“Everything is still in Diane’s design,” Rayni Williams, who — along with Branden Williams of the Beverly Hills Estates — represents this listing, previously told The Post.

In 2010, Keaton sold it to the writer and director Ryan Murphy for $10 million. In 2021, Murphy sold it to the current owners, Seth and Cailin Wunder. He’s a hedge fund manager and she’s a designer.

Today, a new buyer can get about 8,400 square feet with six bedrooms and nine bathrooms. There’s also a living room with a fireplace, a primary bedroom with a fireplace, a gym and a wine cellar.

Elsewhere, there’s a guesthouse, a pool, a spa, a sports court and a two-car garage.