Antonella is Gio's younger sister. She is first seen at the show Wicked which she attends with Gio. As Betty has lied to Daniel and told him that she is dating Gio, Antonella must sit with Henry. She tells Henry that Betty is "macking on her brother". She is later seen in Season 2 where she is attending a dance at the same high school as Justin. Betty talks to her about her article and Antonella tells her that her brother, Gio is a chaperone as well.