Willie Garson Kept Cancer Battle from 'And Just Like That...' Costars Except Sarah Jessica Parker

Many of Willie Garson's And Just Like That... costars were unaware of his private cancer battle.

Garson, who played Stanford Blatch — the best friend of Sarah Jessica Parker's Carrie Bradshaw — in the Sex and the City franchise, died of pancreatic cancer in September. He was 57.

"The death of Wille Garson was obviously, completely unlooked for, unknown," Cynthia Nixon said Friday during press interviews for the HBO Max revival of the original series, according to Deadline.

She added that Parker "was the only one that knew he was sick when we were filming until things became undeniable and then we were told."

"Thankfully we were able to shoot with him not just before he was sick but after so it could be something we could discuss and listen to him about," she continued. "I know that was very important for us and I think it was something that was important to him, too — not to be hiding that from us anymore."

She concluded, "As Charlotte [Kristin Davis] says, 'Death is a part of life,' but it does remind us of how precious our loved ones are to us."

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Garson had already filmed scenes for the Sex and the City revival before his death, and he is seen in the first two episodes that are currently streaming on HBO Max. His death will not be written into the plot of And Just Like That..., showrunner Michael Patrick King told The New York Times last week.

"Nobody's dead," he said. "Because it wasn't charming. And I knew that the audience would know."

In September, Parker shared a touching tribute to Garson on Instagram with a series of photos of them from over the years.

"It's been unbearable," she began her caption. "Sometimes silence is a statement. Of the gravity. The anguish. The magnitude of the loss of a 30 + year friendship."

She continued, in part, "A real friendship that allowed for secrets, adventure, a shared professional family, truth, concerts, road trips, meals, late night phone calls, a mutual devotion to parenthood and all the heartaches and joy that accompany, triumphs, disappointments, fear, rage and years spent on sets (most especially Carrie's apartment) and laughing late into the night as both Stanford and Carrie and Willie and SJ."

"Willie. I will miss everything about you. And replay our last moments together. I will re-read every text from your final days and put to pen our last calls," Parker wrote. "Your absence a crater that I will fill with blessing of these memories and all the ones that are still in recesses yet to surface."

In a statement to PEOPLE at the time of his death, a spokesperson for HBO/HBO Max said, "Willie Garson was in life, as on screen, a devoted friend and a bright light for everyone in his universe. He created one of the most beloved characters from the HBO pantheon and was a member of our family for nearly twenty-five years. We are deeply saddened to learn of his passing and extend our sincere condolences to his family and loved ones."