The 52-year-old chat-show host has paid a heartfelt tribute to the late actor, who died of natural causes at the age of 86 on Friday (15.05.20), describing Willard as an uplifting figure in his life.
Jimmy shared: "In a lot of ways, Fred Willard was like a Christmas tree in June - a little weird, familiar but still surprising to see it, full of good memories and you're just instantly happy that it's there."
The TV star - who dedicated Monday night's (18.05.20) episode of 'Jimmy Kimmel Live!' to his showbiz pal - thinks Willard made a positive impression on everyone who ever met him.
Jimmy said: "He was more than just funny. He had a light inside him; you could see a glint of it in his eyes. And it made everyone around him happy."
Hope Mulbarger, Willard's daughter, paid tribute to the comedy star shortly after he passed away.
She said: "My father passed away very peacefully last night at the fantastic age of 86 years old.
"He kept moving, working and making us happy until the very end. We loved him so very much! We will miss him forever."
Meanwhile, Glenn Schwartz, the later actor's rep, also paid a glowing tribute to Willard.
He shared: "A four-time Emmy nominee radiated a unique charm that established him as one of our generation's most gifted comic actors.
"A master of sketch comedy, Fred was most heralded for his quick wit and improvisational expertise, which he demonstrated in hundreds of appearances on stage, on the big screen, and on a wide range of television shows."