'Sex and the City' Star Willie Garson Dead at 57

Willie Garson -- famous for his role in the "Sex and the City" series and movies -- has died ... according to his close friends.

"Bosch" star Titus Welliver broke the news of Willie's passing with a post that said, "There are no words. I love you dear brother. We are fewer," and he attached a photo of Willie.

Willie's fellow actor and friend Rob Morrow also posted a tribute.

Sources connected to the 'SATC' star tell us he'd been battling cancer, though we've not confirmed it as his cause of death.

Willie was a fan fave from the hit HBO series ... playing Sarah Jessica Parker's male BFF, Stanford Blatch -- a gay socialite who Carrie Bradshaw often called "Stanny."

He didn't appear in every episode, but for the 27 he did pop up for over the course of 6 years ... his scenes were always memorable.

Willie was also in both 'SATC' movies ... and he's at least slated to appear with SJP and co. in "And Just Like That..." -- the new HBO Max series. We know he shot scenes in NYC this summer with Sarah Jessica and Mario Cantone.

WG's roles went well beyond 'SATC' though -- he's been in tons of shows and movies throughout his career ... including stuff like "White Collar," "Hawaii Five-0," "Quantum Leap," "Girl Meets World," "Mr. Belvedere," "Just Shoot Me!" "Big Mouth," "Supergirl," and many, many more.

He's got a total of 170 acting credits to his name, dating back to the '80s.

Willie was 57. He leaves behind his son, Nathen.