Each star spoke about Willard and the effect that he had on their lives and careers from their homes on Monday.
Willard, a comedian known for starring in Everybody Loves Raymond, Modern Family, and several mockumentaries from filmmaker Christopher Guest, died recently at the age of 86. No cause of death was specified.
"Fred was so wildly inventively funny but also so unbelievably strong in the best way," O'Hara, who appeared with Willard in film Waiting for Guffman said.
"He was a true improvisational genius and the nicest man you could ever want to meet," Levy, who worked with Willard on a number of films including Best in Show.
"I was so heavily influenced by Fred's style as a performer and his good-natured obliviousness that there would be no Phil Dunphy without Fred Willard," Burrell said, referencing his Modern Family character. Willard appeared on the sitcom as the father of Phil.