One of the most popular shows of all time, and easily the most popular animated show is The Simpsons. From its first appearance on The Tracey Ullman Show in 1987, The Simpsons has entertained millions. But, here are 7 Things You Don’t Know About: The Simpsons.

1. The Simpsons debuted as an animated short production on the Fox television series The Tracey Ullman show. After its success as its own series, Tracey Ullman sued Fox saying that a large part of The Simpsons success was due to her show and she deserved some of the profits. The suit was dismissed by the courts.

2. Famous singer Tony Bennett was the first guest star to appear on The Simpsons as himself.

3. In the December issue of Time Magazine, The Simpsons was named the 20th century’s best television program.

4. The initial drawings of The Simpsons characters were issued by creator Matt Groening as sketches that he assumed would be “cleaned up” in production. Animators assumed this was the desired style and this is the reason for the characters’ even more crude appearance in the initial short episodes.

5. Homer Simpson’s famous “D’oh” has since been added to most dictionaries.

6. The first celebrity to both guest star and write an episode of The Simpsons was English comedian and actor Ricky Gervais.

7. Famous late night talk show host Conan O’Brien was a writer for The Simpsons during its early years.

The Simpsons have built up a huge following over their more than 20 years on television, and nothing appears to be slowing them down anytime soon.