Laura Prepon played the main role of Donna Pinciotti in the series from 1998 until 2006. According to Us Weekly, her older brother Brad Prepon died suddenly on Wednesday, July 15. Laura Prepon Describes Her Brother as ‘A Singular, Beautiful, Inimitable Force’Laura Prepon shared the news of her brother Brad’s passing with the 11 million followers on her Instagram account. For those of you who knew Brad, I’m so happy he touched your lives. We’d like to send our heartfelt condolences to the family and friends of Brad Prepon — including, of course, Laura Prepon — at this upsetting time.