The 1988 Primary Five class of Primate Dixon Primary School in Coalisland, had just finished Dahl's Danny, the Champion of the World, when they decided they should write to the author.
It was not long before the creator of Willy Wonka, Miss Trunchbull and the Twits replied in his own unique style.
According to The Irish News, it was addressed to teacher James Maye and his class and Dahl's poem contrasted the Tyrone schoolteacher's approach to that of his own.
"From your letters to me it would seem, That your teacher is clearly a dream. There's no whacks on the bum, When you can't do a sum, Instead you get strawberries and cream", he wrote.
But the letter and poem were placed in a drawer where, for almost 30 years, Dahl's correspondence did little but gather dust.
"It wasn't until 2012 that our vice principal Siobhan Murphy was clearing out an old desk, an old desk that could easily have been thrown out,  and came across the letter," Primate Dixon's principal Sean Dillon told the BBC.
He said  the school "knew straight away" of the significance of their literary find.
The principal's initial research showed the previously unpublished poem had since been printed in the 'Roald Dahl Treasury', a 1997 anthology of unpublished works.
On Tuesday, the letter and poem went on display at the school to mark the centenary of Dahl's birth.
Mr Dillon said everyone connected to the school is "extremely proud" of their link to the literary great.
Dahl's books have long been the bedrock of countless childhoods.
More than 200 million copies have been sold worldwide and translated into 59 languages.
A long-lost Roald Dahl poem penned for pupils at a County Tyrone primary school is on display to mark the author's 100th birthday.