We have been inundated with a wealth of fantastic photos after putting out an appeal for them on Facebook.
This gallery has been updated throughout the day as more and more pictures have been sent over!
MORE: Best World Book Day photos from 2021, World Book Day excitement grips Portsmouth as children become their favourite superheroes
Unfortunately due to the overwhelming amount of photos we were sent and time constraints, we have not been able to feature every single one sent to us today – despite hoping to be able to do so.
But we tried to feature as many as possible - and there are over 50 images in our gallery!
The gallery is at the bottom of this article – and make sure to click through all the pages!
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17. Billionaire Boy
Noah Powell from Waterlooville dressed as Billionaire Boy for World Book Day. Photo: Carlie J. Powell
18. Dorothy
Martha aged 9 from Havant dressed as Dorothy from the Wizard of Oz for World Book Day. Photo: Katy Cairns
19. Mr Strong
Tommy age 8 dressed as Mr Strong from the Mr Men books for World Book Day. Photo: Lisa Floyd
20. Rapunzel
Ezri, 2, and dressed up as Rapunzel for World Book Day. Photo: Sophie Rebecca Fitzpatrick