The Simpsons episode penned by the director of Knocked Up will air this week 25 years after it was written.

Judd Apatow, also known for The 40-Year-Old Virgin and Girls, sent his script to The Simpsons producers back in 1990 but did not receive a response.

The Golden Globe nominee, then aged 22, had yet to make a name for himself as a comedy writer, and The Simpsons itself was only just beginning.

Apatow brought up his mysterious lost episode during an interview last year, prompting the animated show’s executive producer Al Jean to dig it out and finally bring it to life.

Titled “Bart’s New Friend”, the episode will air this coming Sunday on US network Fox. A UK broadcast date has yet to be announced but is expected soon.

“It’s a pretty rough script,” Apatow told TV Guide. “When I reread it I wasn’t exactly glowing with pride but Al and the staff did their Simpsons magic on it.

“They were very collaborative and very respectful but everything they wanted to do was so much better than anything I could think up. They turned my messy little effort into Cinderella.”

“I realised that everything I had ever written was the premise of the first thing I had ever written,” Apatow said. “All of my stories are about people trying hard not to grow up.”