Shain Gandee's costars took to Twitter to express their grief in the hours after his death.
"I just don't understand," tweeted Shae Bradley. "Just woke up and it's not all just a night mare."
"Rip Shain Gandee. You are an angel, I know you will watch over me," wrote Ashley Whitt.
ABC News' Suzan Clarke and Josh Haskell contributed to this report.