Fashion Police panelist and longtime friend of Joan Rivers posted a heartfelt message about the late comedienne on social media on Thursday evening.

As previously reported by TheCelebrityCafe.com, Joan Rivers passed away at the age of 81 after suffering complications during surgery at a New York City surgery center.

Kelly Osbourne worked alongside Rivers on E! Network’s Fashion Police for years and developed a close relationship with the legendary comedienne. Osbourne took to Facebook to voice her regret over Rivers’ passing.

“I'm completely heartbroken by the loss of my beloved Joan,” Osbourne began. “Not only was she my boss, she was and will always be my teacher, therapist, closest friend, inspiration and the only grandmother I ever knew. She was family and I will never forget her.”

Osbourne wrote more about the nature of their relationship while sending her prayers to Rivers’ daughter, Melissa. She then thanked Rivers for her support and friendship over the course of her lifetime.

“Joan, thank you for taking me in and loving me as a daughter. I will miss you deeply and will always hear your voice in my head saying ‘my darling get out there and be you!’ ”

Rivers’ funeral will be reportedly held at a synagogue in New York this weekend.

Image courtesy of Kristin Callahan/ACE/INFphoto.com