Diane Keaton has died at the age of 79 (Image: AP)

Diane Keaton’s sudden d3ath at the age of 79 has left her fans, friends and former co-stars shocked.

The Father of the Bride star passed away in California, surrounded by her loved ones, her spokesperson confirmed.

Since news of her d3ath emerged, several celebrities have paid tribute to the actress, including Robert De Niro and Better Midler.

Now, Diane’s cause of d3ath has been confirmed. In an exclusive statement to PEOPLE, the Oscar-winning actress’s family confirmed she died of pneumonia on Oct. 11 and expressed their gratitude for fans’ support in an emotional message.

“The Keaton family are very grateful for the extraordinary messages of love and support they have received these past few days on behalf of their beloved Diane, who passed away from pneumonia on October 11,” reads the statement.

Her cause of d3ath has now been confirmed (Image: Getty Images)

Keaton’s family went on to share the causes she was passionate about, “She loved her animals and she was steadfast in her support of the unhoused community, so any donations in her memory to a local food bank or an animal shelter would be a wonderful and much appreciated tribute to her.”

The actress was known for starring in films including The Godfather and Annie Hall – and she has left a lasting legacy in Hollywood.

De Niro who worked with Diane several times since The Godfather Part II, said in a statement, “I am very sad to hear of Diane’s passing. I was very fond of her, and the news of her leaving us has taken me totally by surprise.

“I was not expecting her to leave us. She will be missed. May she rest in peace.”

Bette, who starred in The First Wives Club with the actress, said, “The brilliant, beautiful, extraordinary Diane Keaton has died. I cannot tell you how unbearably sad this makes me.

“She was hilarious, a complete original, and completely without guile, or any of the competitiveness one would have expected from such a star. What you saw was who she was … oh, la, lala!”

Woody Allen, who met the star at work and then had a relationship with her, was said to be “distraught” to learn of her passing.

The pair remained close friends over the years. A source told People that Woody, 89, feels “extremely distraught and surprised and upset” about Diane’s d3ath, adding “it makes him think of his own mortality.”

The source pointed out that Woody “appreciated her very much” and that he was unaware of her deteriorating health.

Woody Allen is said to be ‘distraught’ following Diane’s d3ath (Image: Getty Images)

“Nobody seemed to know,” the insider revealed. “He was surprised.”

In her memoir, Diane reminisced about Woody, writing, “He was so hip, with his thick glasses and cool suits.

“But it was his manner that got me, his way of gesturing, his hands, his coughing and looking down in a self-deprecating way while he told jokes.”