Doris Day Mourned by Paul McCartney, William Shatner, Goldie Hawn and More Hollywood Stars

Doris Day has died at 97 and Hollywood is mourning America’s sweetheart.

The Hollywood icon died at 1:00 A.M. on Monday at her home in California, her rep tells PEOPLE.

Day shared a special friendship with Paul McCartney, who posted a tribute to her on Instagram on Monday.

“So sad to hear of Doris Day passing away. She was a true star in more ways than one,” he wrote in the caption. “I had the privilege of hanging out with her on a few occasions.”

He continued, “Visiting her in her Californian home was like going to an animal sanctuary where her many dogs were taken care of in splendid style. She had a heart of gold and was a very funny lady who I shared many laughs with. Her films like ‘Calamity Jane’, ‘Move Over, Darling’ and many others were all incredible and her acting and singing always hit the mark.”

“I will miss her but will always remember her twinkling smile and infectious laugh as well as the many great songs and movies she gave us,” he added. “God bless Doris.”

William Shatner also shared his thoughts on the Pillow Talk star, tweeting, “Condolences to the family of Doris Day. She was the World’s Sweetheart and beloved by all. Que Será, Será!”

Goldie Hawn followed suit, tweeting, “The great Doris Day left us and took a piece of the sun with her. She brighten [sic] our lives and lived out her life with dignity. May she rest peacefully.”

Singer Tony Bennett shared his condolences on Day’s passing with a video clip of when he appeared on The Doris Day Show in 1970.

“Susan and I are saddened to hear of Doris Day’s passing. She was a wonderful friend to us and a lovely and very talented lady,” he wrote on Twitter. “We will miss her beautiful smile and it was such a thrill to appear on The Doris Day Show back in 1970.”James Duke Mason, the grandson of actor James Mason, tweeted a photo of his grandfather with Day and Judy Garland on the set of A Star Is Born, which Mason and Garland starred in together in 1954.

The Associated Press was first to report the news of her death, which comes nearly two months after the actress celebrated her birthday and shared a recent photo with PEOPLE.

Although in 2012 she released a CD of songs she recorded years ago, since the early ’80s, the world’s favorite “girl next door” kept a low profile and lived on 11 acres in Carmel, California, where she devoted most of her time to her charitable organization.

For Day, as she told PEOPLE in 2011, her greatest loss in life was the 2004 death (from melanoma) of her son, music producer Terry Melcher.

“I had him when I was [18], so we were like sister and brother,” said Day, who found his passing “really hard. But I keep him with me.”

The profile also pointed out that humor had always been Day’s secret weapon. “I love to laugh,” said the star who made so many others laugh and sing. “It’s the only way to live. Enjoy each day — it’s not coming back again!”