Bob Saget has died at the age of 65

 Bob's longtime friend and costar John Stamos just tweeted the following, "I am broken. I am gutted.  I am in complete and utter shock.  I will never ever have another friend like him.  I love you so much Bobby."

The Orange County Sheriff's Office tells us, "We have no information on cause of death, and detectives have found no signs of foul play or drug use in this case." They note, "the Medical Examiner’s Office will make the final call on the cause and manner of death."

Bob Saget has died at the age of 65 ... TMZ has learned.

Multiple sources connected to the iconic comedian and actor -- most famous for his starring role as Danny Tanner in 'Full House' -- tell us he passed away Sunday at the Ritz-Carlton in Orlando.

The Sheriff's Department and the fire department responded to the hotel around 4 PM ET ... after hotel security had found Bob in his room. We're told he was pronounced dead on the scene, but the circumstances of his death are still unclear.