Credit: Dominique Charriau/; Todd Williamson/

Sarah Jessica Parker captivated viewers as unlucky-in-love Carrie Bradshaw for six years on HBO's Sex and The City. Though Parker has reprised the role twice on the big screen, actress AnnaSophia Robb will get her chance to portray the beloved character in a new CW prequel, The Carrie Diaries, premiering this fall.

Robb has even received a blessing from mom-of-three Parker, 46.

"She sent me a letter! I wrote her one back, too," Robb, 18, told Us Weekly at the launch of Salvatore Ferragamo's Signorina fragrance in NYC Tuesday. "She was just very encouraging about it all. It was really cool!"

Robb began filming her first episode in the Big Apple Wednesday, but her preparation began months ago. "We've been doing a lot of rehearsals this week, and I've been watching the show and really trying to click with the character," she said.

Though The Carrie Diaries will inevitably elicit mixed reviews from critics, Robb isn't worried about being compared to the HBO hit.

"I know everyone's going to compare it to Sex and the City, but we're never going to be that," she told Us. "The show is more for my generation, but it's set in the '80s, so it's fun."

Prior to being cast in The Carrie Diaries, Robb was best known for her roles in Bridge to Terabithia, Race to Witch Mountain and Soul Surfer.