After her Ugly Betty appearance, the producers of Sex And The City The Movie, decided they want Victoria Beckham to have a cameo in the movie. Posh had to say no as she's busy with the Spice Girls reunion:

"I got asked to be in the Sex And The City film, which I would have loved to have done, but because I am in full-on Spice Girls rehearsal mode, unfortunately, I can't do it right now."

even though, she did not help anything and even singing for spice. she decided not to be in Sex And The City. you know, she can't really act or sing so what's the big idea of having her both in the Sex and the City and do the rehearsal with the Spice Girls.