Prince George celebrates his fourth birthday today (22 July).

To mark the special occasion, his parents shared an adorable portrait of the birthday boy. The official photo captures the young prince beaming into the camera with a toothy grin.

"The Duke and Duchess are very pleased to share this lovely picture as they celebrate Prince George's fourth birthday, and would like to thank everyone for all of the kind messages they have received," a statement from the palace read.

The photo was taken at Kensington Palace at the end of June by Chris Jackson, the royal photographer for Getty Images. It was released at the end of Kate and William's week-long tour of Poland and Germany with their two children.

Prince George has enchanted millions worldwide with his cheeky personality and endearing expressions.

From acting as a page boy at his aunt Pippa Middleton's wedding to his meeting with US president Barack Obama, here are some of the young prince's most memorable moments:

George makes his first public appearance outside St Mary's Hospital in London on 23 July 2013Reuters
Prince George appears in a new photo shoot with Kate Middleton, Prince William/Reuters
The happy family in the garden of the Middleton family home in Bucklebury, Berkshire
Prince George and Prince Charlotte
Prince George holds his new baby sister Princess Charlotte on 8 June 2015Handout/Getty
US President Barack Obama with children
Prince George meets US President Barack Obama at Kensington Palace on 22 April 2016Official White House Photo by Pete Souza
Pippa Middleton's wedding
Prince George is told off by his mother at his aunt Pippa Middleton's wedding on 20 May 2017AFP/Getty Images
Prince George
The young prince pulls a face while watching the Trooping the Colour parade on 17 June 2017 in London, EnglandChris Jackson/Getty Images
Prince George
The Duke and Duchess of Cambridge have released an official portrait of Prince George to mark his 4th birthdayAFP/Getty