Jimmy Fallon Announces Death of Family Dog Gary

Jimmy Fallon is heartbroken ... revealing his beloved family dog has passed away.

On IG Monday, the talk show host posted sweet snaps of their pup Gary -- writing a heartfelt tribute about how the silence at home feels deafening without her ... but that it’s slowly being filled with stories, laughter, and a few sniffles.

Jimmy even shared a few of those memories -- calling the unforgettable pup their "first baby, a therapist, a pillow, a big sister, a schoolmarm, a comedian, a party girl and a rebel" all rolled into one.

Jimmy first introduced Gary to his IG followers way back in 2012 -- so it’s clear she’s been a huge part of the family’s life for over a decade.