Willie Garson, the actor famous for his role as Stanford Blatch on Sex and the City, has died at the age of 57. His death was confirmed by his family, who posted a heartfelt tribute, but the cause of death has not been confirmed.

With the Sex and the City reboot series just around the corner, cast and crew recently spoke to People. They said Willie Carson had been battling pancreatic cancer. But it has not been revealed whether that was the cause of death.

Throughout the famous HBO series, Willie Garson’s character “Stanford Blatch” was the best friend to Sarah Jessica Parker’s character, “Carrie Bradshaw.” He appeared in 27 episodes of Sex and the City, both of the movies, and had just wrapped up his appearance on the sequel series, titled And Just Like That…

“I love you so much papa,” Willie’s son Nathan wrote on Instagram, announcing his death. “Rest In Peace and I’m so glad you got to share all your adventures with me and were able to accomplish so much. I’m so proud of you.”

“I will always love you, but I think it’s time for you to go on an adventure of your own,” Nathan continued. “You’ll always be with me. Love you more than you will ever know and I’m glad you can be at peace now. You always were the toughest and funniest and smartest person I’ve known. I’m glad you shared your love with me. I’ll never forget it or lose it.”

A spokesman for HBO also confirmed Willie Garson’s passing, writing that, “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,” the statement read. “We are deeply saddened to learn of his passing and extend our sincere condolences to his family and loved ones.”

Aside from Sex and the City, Willie also appeared on television shows such as Quantum Leap, Twin Peaks, Boy Meets World, The X-Files, NYPD Blue, Melrose Place, Ally McBeal, Friends, Monk, CSI Miami, Wizards of Waverly Place, Medium, the 2015 reboot of Hawaii Five-0, and countless others.

“So deeply, deeply sad we have lost Willie Garson,” co-star Cynthia Nixon, who played “Miranda Hobbes” on Sex and the City, wrote on Twitter. “We all loved him and adored working with him. He was endlessly funny on-screen and and in real life. He was a source of light, friendship and show business lore. He was a consummate professional— always.”

“Such sad news and a terribly sad loss to the SATC family,” wrote Kim Catrall, a.k.a. “Samantha Jones” on the HBO series. “Our condolences and RIP dear Willie xo.”

In a heartbreaking message, Mario Cantone, who played Willie Garson’s on-screen husband on Sex and the City, said that he “couldn’t have had a more brilliant TV partner.”

“I’m devastated and just overwhelmed with sadness,” Mario Cantone said. “Taken away from all of us way soon. You were a gift from the gods sweet Willie. Rest …I love you.”

In a message to Willie Garson’s son, Nathan, comedian Ben Stiller said that he was grateful that he knew him. “Your dad was strong and respected in his community of fellow actors and his philanthropy was constant and committed,” Stiller wrote. “He was also really really funny.”

Earlier this month on Sep. 5, Willie sent a message to his fans, which is now his final message, that simply read, “BE KIND TO EACH OTHER……ALWAYS.”