For fans of Frankie Knuckles, Monday will forever be remembered as the day the house music died.

The Bronx-born DJ, saluted as the "Godfather of House," passed away "unexpectedly" at home at the age of 59, his business partner, Frederick Dunson, told the Chicago Tribune. The cause of death has not been confirmed, but reports say Knuckles did suffer from Type II Diabetes and other health issues that led to a 2008 foot amputation.

After starting out in the industry with friend and fellow DJ Larry Levan at Manhattan's Continental Baths, the pioneer changed dance music forever at Chicago club the Warehouse (believed to be where house music got its name) in the late 70s and early 80s with his unique remixes, blending of genres and marathon sets, and then opened his own place, the Power Plant. He later returned to New York City for club residencies at the Sound Factory and the Roxy, among other hot spots, and went on to form Def Mix Productions with DJ David Morales. He worked with legendary stars including Diana Ross and Michael Jackson.

Frankie Knuckles Day has been celebrated in Chicago on Aug. 25 since 2004 thanks to a push from then-senator Barack Obama.

Members of the popular-as-ever house music community took to Twitter to mourn their loss, which happened just a day after Ultra Music Festival, one of the biggest DJ gatherings of the year, ended in Miami.

"jesus man. Frankie Knuckles was so under-appreciated. he was the dj that dj's aspired to be. true dance pioneer," drummer and DJ Questlove Jenkins tweeted.