Kermit has often been referred to as Henson's "soft-spoken alter-ego." Many of Henson's colleagues have confirmed how close and inseparable Jim and Kermit's personalities were. Henson's agent Bernie Brillstein has stated straightforwardly that "Kermit was Jim". Author Brian Jay Jones described the relationship accordingly: "The more Jim performed Kermit, the more the two of them seemed to become intertwined…it was becoming harder to tell where the frog ended and Jim began." Henson continued to perform the character until his death in 1990. Henson's last known performance as Kermit was for an appearance on "The Arsenio Hall Show" to promote "The Muppets at Walt Disney World". Henson died twelve days after that appearance.