Puss-in-Boots is a talking cat; though a fairy tale character, he does exist in some shape or form.
Although Scrooge McDuck knew Puss-in-Boots as a fictional character, Gyro Gearloose was, in 1969, able to use his Fantasy Finder to meet Puss-in-Boots. The two seemed to hit it off, with the cat letting the inventor take the Seven League Boots home.
Behind the scenes
Puss-in-Boots is mentioned in the 1969 story The Golden Apples.