Laughter of the Gods
One day in 1964, Kenneth Tynan went out to lunch with Groucho Marx and S.J. Perelman. He wrote an article about it, which was published in the Observer on June 14, 1964. The following is an excerpt from that article.

I asked him [Groucho] to name the people who have made him laugh. "The funniest talkers," he says, "the funniest men around a dinnertable would be George Jessel and George Burns. The fastest men with one-line gags would be Oscar Levant and George S. Kaufman. On stage, I would pick W.C. Fields, Willie Howard, Ed Wynn, Bobby Clark and Bert Lahr. But it's hard to laugh at comedians if you're a comedian, especially if they're getting laughs." Perelman's list of great comics is the same, except that it includes Groucho.