Actor Sam Neill, famous for his role as Dr. Alan Grant in Jurassic Park, recently published his memoir, Did I Ever Tell You This? The 75-year-old actor shared memories about his late colleague and friend Robin Williams, with whom he shared a set for Chris Columbus’ Bicentennial Man.

In the memoir, Neill calls Williams “The saddest person I ever met” despite remembering excellent and fun moments with him and also describing the actor as “irresistibly, outrageously, irrepressibly, gigantically funny.”

Williams passed away at age 63, on August 11, 2014, because of suicide.

Neill writes in his memoir:

“He had fame, he was rich, people loved him, great kids—the world was his oyster. And yet I felt more sorry for him than I can express. He was the loneliest man on a lonely planet.”

 The actor describes Williams as “inconsolably solitary and deeply depressed.” He observes that “funny stuff just poured out of him.” Meaning that humor seemed to be something that helped Williams to soothe his feelings. Neill continued, “And everybody was in stitches, and when everybody was in stitches, you could see Robin was happy.”