Katharine Hepburn left an estate estimated at $40 to $50 million — with many millions in priceless movie memorabilia hidden away in her Connecticut home.

Friends said Katharine saved many of her costumes and props from hit movies such as “The African Queen” and “Adam’s Rib” — not to mention her four Oscars and numerous other awards, now all worth millions.

Her real estate holdings are worth a fortune. Her 8,000-square-foot waterfront home in Old Saybrook is believed to be worth $10 to $12 million.

The actress never sold her Manhattan town house when she moved to Connecticut for good in 1996. It too could draw $10 million.

In addition to her earnings from her Hollywood career, the actress also pocketed a reported $4.25 million for her best-selling 1991 autobiography, “Me: Stories of My Life.”

And she was downright “frugal” all her life, said Stephen Silverman, an author and longtime friend.

“She didn’t spend on clothes and was a real homebody. She always preferred a home-cooked meal to a fancy restaurant or a night on the town.”

Katharine’s heirs include her younger sister Peg Perry and 13 nieces and nephews.

Her longtime housekeeper and companion Norah Moore may also be remembered in the star’s will.