"Donnie Fatso" is the ninth episode of the twenty-second season of the animated comedy series The Simpsons. It first aired on Fox in the United States on December 12, 2010. The plot revolves around an FBI agent, who helps Homer go undercover to infiltrate Fat Tony's mob. Homer agrees to this in hopes of decreasing his sentence after being charged for bribery. This episode is a reference to Goodfellas as well as real-life informant Donnie Brasco. "Donnie Fatso" was written by Chris Cluess and directed by Ralph Sosa. Critics were polarized with the episode, with criticism stemming from its main plot and cultural references. Upon its initial airing, the episode received 7.32 million viewers and attained a 3.2/8 rating in the 18-49 demographic, according to Nielson ratings. "Donnie Fatso" featured guest appearances from Jon Hamm and Joe Mantegna, as well as several recurring voice actors and actresses for the series.