PALM DESERT ( — A longtime physician and close friend of late pop legend Michael Jackson has died in Palm Springs, authorities confirmed Friday.

Dr. Arnold Klein, 70, died Thursday night at the Eisenhower Medical Center, according to the Palm Desert Coroner’s office.

READ MORE: Protests Continue Outside Sigma Nu House On USC's Fraternity Row As New Sexual Assault Allegations Emerge

His death was attributed to natural causes, according to reports.

A prominent Beverly Hills dermatologist, Klein had reportedly injected Jackson with a popular brand of painkiller over 50 times in the weeks prior to his death, according to TMZ.

Klein and Conrad Murray were Michael Jackson’s key physicians during the pop star’s final weeks in June 2009.

Murray was convicted of involuntary manslaughter in Nov. 2011 and was sentenced to four years in county jail. Due to California sentencing rules, he became eligible for parole in half that time and was released.

READ MORE: Lawmaker Calls For Change On California Film Sets After Prop-Gun Shooting Death Of Halyna Hutchins By Alec Baldwin

Klein, who treated Jackson for more than 25 years and called him “my best friend,” was cleared of any wrongdoing by authorities.

Veteran Hollywood publicist Michael Levine told KNX 1070 NEWSRADIO that Klein faced personal and professional challenges in the wake of Jackson’s death in 2009.

“There’s no question that Arnold Klein was a pioneer in the field of dermatology and Botox, and there was also no question that his career, which was spectacularly successful at a certain point, became really drowned in controversy,” said Levine. “Ultimately, I think, [that] took a deep emotional toll on him.”

Some of Hollywood’s biggest names are reportedly among Klein’s former clients, including Elizabeth Taylor, Goldie Hawn, Dustin Hoffman, Dolly Parton, and Sharon Stone.

In addition to his dermatology career, Klein also founded the American Foundation for AIDS Research and the Elizabeth Taylor AIDS Foundation with Taylor.

MORE NEWS: Inland Empire Commuters Dealing With Wet And Dangerous Road Conditions

(TM and © Copyright 2015 CBS Local Media, a division of CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2015 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)