Michael J. Fox's beloved dog, Gus, has died. The Back to the Future star, 59, announced the sad news on Monday, sharing a photo of the 12-year-old pooch on his Instagram. "Gus — great dog and loyal friend, we'll miss you," he wrote in the caption, before referencing several pages from his 2020 memoir, No Time Like the Future: An Optimist Considers Mortality. In addition to his tribute, Fox also posted numerous photos of himself with Gus throughout the years on his Instagram Stories.