Eagles Guitarist Glenn Frey Dies at 67

The rock group's founding member 'succumbed to complications from rheumatoid arthritis, acute ulcerative colitis and pneumonia.'

Glenn Frey, founding member and guitarist for the Eagles, died on Monday at 67 years old, ET confirms.

In a statement posted to the musician’s website, Frey’s family announced that he “succumbed to complications from rheumatoid arthritis, acute ulcerative colitis and pneumonia.”

“The Frey family would like to thank everyone who joined Glenn to fight this fight and hoped and prayed for his recovery,” the statement continued. “Words can neither describe our sorrow, nor our love and respect for all that he has given to us, his family, the music community & millions of fans worldwide.”

PHOTOS: Stars We've Lost In Recent Years

A source told ET that Frey’s death was “a shock to everyone.”

“He has been very sick for the last few months, but the band really did believe he would heal fully,” the source said.

Frey co-wrote and sang many of the group’s hit songs, including “Take it Easy,” “Lyin’ Eyes," and Heartache Tonight.” He also co-wrote “Hotel California” and “Desperado” with Don Henley, and won 6 GRAMMY Awards as part of the group.

After the Eagles split in 1980, Frey went on to a successful solo career, which included hits like “The Heat is On” from 1984's Beverly Hills Cop. The band later reunited in 1994 for the Hell Freezes Over tour, and continued recording and touring through 2015.

WATCH: Miranda Lambert Covers The Eagles' 'Desperado' In Show-Stopping Kennedy Center Honors Performance

The Eagles were forced to delay their Kennedy Center Honor in November 2015, citing Frey’s health issues. According to a statement from the band at the time, Frey was suffering from “intestinal issues, which will require major surgery and a lengthy recovery period.”

He is survived by his wife, Cindy, and three kids, Taylor, Deacon, and Otis.