Hollywood is still reeling from the sudden death of ground-breaking comedian Garry Shandling. The 66-year-old suffered a massive heart attack at his Los Angeles home on Thursday, March 24, and was later pronounced dead at St. John's hospital.

According to TMZ, there were signs that Shandling's health was failing the night before he passed away. Sources tell the news outlet "he spoke with a doctor friend of his Wednesday late afternoon, complaining he was not feeling well. The doctor was concerned enough that he came to Shandling's home and checked him out."

Shandling was apparently short of breath on Wednesday evening and felt "achy." Although the comedian/actor didn't complain of chest pains, his friend urged him to head to the ER if he still felt ill the next morning. Gary agreed to do just that.

Unfortunately, Gary called 911 at 10:30 AM the next day and passed out while on the phone with the operator. Paramedics had to break down his door, where he was found unresponsive.

In memory of Shandling's pure brilliance, here's a look back at a clip from HBO's "The Larry Sanders Show," which, along with "The Garry Shandling Show," changed the game.

Shandling is credited with inventing the laugh-track-free single-camera sitcom. So we can thank him for "The Office" (British and American), "30 Rock" and "Modern Family" just to name a few.

This clip also features a guest appearance from the late great Robin Williams and it's hysterical:

Shandling once said of his craft, "A great boxer makes his opponent fight his fight, on his terms. A great stand-up takes control of a room. There's a reason comics say their best shows 'killed.' Making people laugh is, at its simplest, an act of domination."

Shandling was, without question, a heavyweight champion of his generation.