Deputy District Attorney Wendy Segall says Zachary Loring entered the plea Monday in Los Angeles and will undergo a 90-day diagnostic evaluation before being sentenced. If found competent, he could be sentenced to up to two years in state prison.
Patridge did not appear in court. She has previously testified in a civil restraining order hearing that she feared Loring, who police say repeatedly went to the starlet's home and left her numerous items, including some disturbing drawings.
The 25-year-old Loring is due back in court on Sept. 20 for sentencing.