Motion picture and television talent agent/manager J.J. Harris died of what is believed to be natural causes on Friday afternoon and was found today in her Beverly Hills home by her staff. She was 62. Always classy and funny but never a pushover, she at one time was among the top women talent agents and sole practitioner managers in Hollywood, representing such notable clients over the course of her decades-long career including Kevin Costner, Charlize Theron, Dakota and Elle Fanning, Kate Bosworth, Drew Barrymore, and Scott Bakula. After starting her career at the old William Morris Agency and jumping to UTA as a partner, she started her own management company more than a decade ago. Harris ran One Talent Management until recently deciding to wind down her business. Until her death, she was spending almost all her time on the career of her longtime confidante and client Costner. It was because of him that her office became worried. “She wasn’t returning my calls or texts. Then Kevin called her,” her assistant and co-manager Sharon Vitro tells me. “It’s one thing for her to ignore me. But she doesn’t ignore Kevin ever.” Her staff went to her home and discovered her body. Through the years, Harris was an outspoken feminist who challenged mano-a-mano the Hollywood men’s club that long ruled actor representation. Bluffing her way into the William Morris accounting department as a secretary, Harris rose through the ranks to become a young but powerful agent best known as fiercely loyal to her clients – even if they weren’t always as loyal to her. (“Every time we’d bring someone up, she’d go, ‘Oh, I used to represent them,'” Vitro recalled.) For instance, Harris had repped the Fanning sisters practically since they were babies, but they followed their other day-to-day One Talent manager out the door at the start of this year. But there was no acrimony when Harris and longtime client Theron parted ways in 2012. (“We had a great run, but Charlize simply doesn’t need a manager right now,” Harris said at the time. “She wants to focus on her production company. We remain friends.” Harris in the mid-1990s signed Theron after the model-actress spilled a Diet Coke on her in a meeting and went on to win an Oscar. Perhaps Harris’ greatest achievement as an agent/ manager was her close personal and professional relationship with the Oscar-winning Costner. She inherited Costner from WME’s Garry Lucchese, fought off WME/ICM’s Ed Limato to keep him, then lost him during the filming of his Dances With Wolves to CAA’s Mike Ovitz, only to represent him again when Ovitz left the agency biz. Meanwhile Costner’s career over the years toggled frequently between hot and cold: with Harris’ help, he scored key recent roles in TV’s Hatfield & McCoys and motion pictures Man Of Steel and the upcoming Jack Ryan and Three Days To Kill. “Nothing made her happier than negotiating a deal,” Vitro recalled. I knew Harris and adored her because she was one tough babe – and proud of it.