Disco superstar Donna Summer passed away this morning , leaving behind a legacy of hits and a legion of fans.

The "Queen of Disco" died at the age of 63, after a battle with cancer.

Sources close to Summer say, the singer was trying to keep the extent of her illness under wraps. Someone who was with the disco singer a couple of weeks ago even says she didn't seem too bad. In fact, sources say she was focused on trying to finish up an album she had been working on.  

Summer was a 5-time Grammy winner who shot to superstardom in the '70s with iconic hits like "Last Dance," "Hot Stuff" and "Bad Girls."

Summer married Brooklyn Dreams singer Bruce Sudano back in 1980 and they had two daughters together. 

Almost immediately after news broke, her fans took to Twitter to remember the star and offer their condolences.

Our condolences to Donna Summer’s family and loved ones!