Best 'City' Friends Forever

It's the ultimate on-screen sisterhood -- four best friends sharing their deepest secrets about life and love. Now, "Extra" is learning that the bond of friendship between the "Sex and the City" ladies is even tighter than we'd known!

In the final season of the TV show, Samantha (Kim Cattrall) delivered devastating news of her cancer -- and now, in a strange coincidence, Cynthia Nixon reveals details about the night a year and a half ago when she told best friend Kristin Davis of her breast cancer.

Davis recalls, "She sits me down in Cynthia fashion and says, 'I have something to tell you. I have breast cancer.'" After a lumpectomy and radiation treatment, Cynthia is now celebrating one year cancer-free -- but says she'll never forget the way her friend reacted. "She stood up on her chair and I couldn't get her to come down until I told her everything I was doing and assured her everything was going to be okay," says Nixon.

The two friends celebrate their sisterhood on the big screen when "Sex and the City" opens May 30th.

Click on an image to view the CELEBRITY BFFS photo gallery!