Michelle Trachtenberg's death Wednesday left her former co-stars like Blake Lively, Rosie O'Donnell, Melissa Gilbert and Kenan Thompson shocked and saddened.

She struggled the last few years. I wish I could have helped."Trachtenberg was found unconscious and unresponsive in her New York City apartment just after 8 a.m. Wednesday, when police and emergency medical workers responded to a 911 call.

O’Donnell was Trachtenberg’s A-list co-star in Harriet the Spy, the 1996 kids movie that marked Trachtenberg’s first major film role (she was just 10 when filming began). O’Donnell played “Ole Golly,” a nanny and mentor to Harriet, the precocious snoop and writer played by Trachtenberg.