Jimmy Kimmel pretends to be Jay Leno for the entirety of his show
One of the most intense late-night controversies occurred in early 2010 when Jay Leno took over The Tonight Show from Conan O'Brien after briefly leaving the program. Fans were furious, accusing Leno of forcing O'Brien off the air—including Jimmy Kimmel, who took the opportunity to dress up like Jay Leno and do an entire episode of his show posing as the talk show host.
While in character as Leno, he claimed that he would be taking over all the talk shows, not just O'Brien's. If it wasn't already apparent, Kimmel always disliked Leno, having openly proclaimed, "F*** him!" However, their feud drew to a close in 2017 when Leno was kind to Kimmel in the aftermath of his son's surgery.