Tonight, Mr Burns's long-suffering assistant Waylon Smithers will come out as gay in a special episode of The Simpsons.

The character, who is voiced by Harry Shearer, has always had an ambiguous sexuality, something that late Simpsons co-creator Sam Simon suggested during Smithers's creation.

Although it's been known since September that Smithers will finally come out of the closet, the writer behind the episode has told the personal story that inspired it: the coming out of his 21-year-old son.

Rob LaZebnik, who has been writing for The Simpsons since 1999, told The New York Post: "I am a Midwestern guy, so I don’t tend to wear my emotions on my sleeve, but I thought, 'What better way to tell my son I love him than to write a cartoon about it?'"

LaZebnik's son Johnny, a student, praised his father for being "unbelievably accepting" and said his parents were understanding when he told them he was gay in high school: "I was the gayest little kid, and my parents knew that. I told them I was interested in a boy. My parents were, like, 'Yeah, we know' "

Smithers's own revelation is similarly understated, the elder LaZebnik explained: "We didn’t really want to have that big moment of 'I’m out,' you know?"