Judy Greer has been orbiting around stardom for the better part of the last 10 years. And although she's had a couple of delicious supporting turns over the years (13 Going On 30, Adaptation, Jawbreaker), she's never quite broken through into the leading lady category ... until now. Ashton Kutcher picked her to be the lead of his new ABC comedy, Miss Guided, and now the lovely and talented Miss Greer is getting her first taste of hitting the promotional circuit as a star. And guess what? She's eating it up. She was as giddy as a school girl during her appearance on The Late Show With David Letterman last night, but also managed to rein in her emotions enough to tell Dave a funny story about how she's still forced to endure some of the humilities that the Hollywood machine puts second fiddles through.