D’oh!

“The Simpsons” writer Al Jean blew a lot of minds this week by tweeting that if the characters on his animated comedy aged, the bratty child character Bart would now be the age his father Homer is on the show.

“If Homer is 39 he was born in 1980 which is when we said Bart was born,” Jean, 59, tweeted Monday.

Making matter worse, Bart’s birthday is Feb. 23, meaning that in three weeks, technically, he’ll be older in actual years than his dopey dad is on the long-running comedy. Instead, Bart will turn 10 on his birthday, as he does every year.

Jean’s Twitter followers have spent the week ruminating about how old that makes them and how old it would make the other characters on the show.

“When the show premiered I was 5 years older than Bart,” tweeted Simpsons fan Brad C. “Now I’m 5 years older than Homer!”

One astonished fan realized Homer is holding back the years, but he can not.

“How did I get to be older than Homer Simpson?” asked Tom Williams.

The official Twitter account belonging to “The Simpsons” pondered that question.

“Honestly, how did you even get older?” that verified account asked.

Chris Spendlove tried to nail down the chronology.

“(Homer) was 38 the whole time and Bart was 10 but Marge got pregnant right after high school … ?”

Gabby Hayes tweeted “Can’t do the math, head going to explode … “

Tweeting at Jean and the show itself, Rocky Buckland offered a couple theories on how the program’s characters stay the same age.

“Ambient radiation from the Nuclear plant has rendered most of Springfield functionally immortal, or at least stunted aging. Some residents die of accidents or tumors, or just move away,” he wrote. “That, or Homer is God and he’s preserving Springfield in a pocket of time forever.”

Simpsons fan Rachel Antolovic tweeted that she doesn’t mind growing old with the show.

“When The Simpsons started on Fox, I was the same age as Bart. I turned 39 a month and a half ago, so I’m Homers age. My fingers are crossed that the show lasts long enough for me to say that I’ll be the same age as Grandpa.”

Grandpa Abraham Simpson is 83, according to Simpsonsfandom.com.