Rouge Bouillon Primary School's parrot turns 70-years-old today.
Sim, who survived a school fire in the 1990s, will receive a specially made birthday cake, which he can share with his human friends, and the school choir will sing him Happy Birthday.
Students have made parrot-themed decorations for his cage.
One Year Five student described his cage as "very dirty".
Sim has helped thousands of new students settle into school life, according to the school.
Deputy head teacher, Jess Doyle says the birthday party is the school's way of "celebrating the contribution Sim has made to life at Rouge Bouillon School over the decades".
Sim used to live at Briggs toy shop, in St Helier, until it closed in 1988.
Since then, he has lived at Rouge Bouillon School after former headteacher Wendy Hurford gave him a home there.
He even survived a fire at the school on 15 April 1991 which started during repairs to the roof.
Staff and children had to leave the building, taking Sim with them but no-one was hurt.