Victoria Beckham shares sweet snap of Harper, 12, dressed as a mouse for World Book Day... before David takes the tail for a VERY cheeky picture

Victoria Beckham revealed daughter Harper was embracing the spirit of World Book Day on Thursday as she dressed up as a mouse.

The former Spice Girl, 49, joined a slew of stars who shared snaps of their children and their costume creations on social media. 

She uploaded a picture of her 12-year-old daughter to her Instagram Stories on Friday, showing off her simple yet effective costume.

Harper donned an all-grey outfit complete with a tail and pair of mouse ears.

Accompanied by a mouse emoji, Victoria captioned the post: 'Dress up for World Book Day (that was actually yesterday).'

Seconds later, Victoria shared a less appropriate use of Harper's school costume as she uploaded a picture of husband, David, 48, wearing the tail between his legs.

Sipping through a straw while sporting eye patches, the football legend was pictured wearing the prop over his crotch with the end tucked between his legs.

Finding the use comical, Victoria captioned the post: 'Dad making good use of the tail' with a flirty smirk emoji.

Rochelle Humes, Myleene Klass and Amanda Holden were among stars celebrating the annual event this year, as they shared adorable snaps of their children dressed as some of the literary world's biggest stars.

In honour of the annual occasion, Rochelle shared cute images of her two youngest children Blake, three, and Valentina, six, dressed as Oompa Loompas from the Roald Dahl classic Charlie and the Chocolate Factory.

Rochelle then shared another snap of her eldest daughter Alaia-Mai, 10, dressed in a look inspired by the Babysitters Club series.

Myleene Klass went to great lengths for her son Apollo in honour of World Book Day, as she and her fiancé Simon Motson built a cardboard train. 

The Smooth Radio presenter posted a video showing the process of building a cardboard version of The Little Red Train, complete a drum filled with sweets for his classmates. 

Amanda Holden  and Ashley Roberts kicked off the celebrations on the Heart Breakfast show by transforming into mystical characters from the world of Narnia.

The pair stunned in their eye-catching costumes after taking inspiration from C. S. Lewis' novel The Lion, the Witch and the Wardrobe.

Donning a sparkly white jumpsuit and fur shrug, Amanda turned into the villainous White Witch for her appearance on the early-morning show.

She finished her look with a matching silver crown as she posed for snaps in the Heart Radio studio.