UK palace releases Prince George's 4th birthday portrait

London: Britain's Prince George turned four on Saturday as his parents, Prince William and Kate, released a new official portrait showing the future British king beaming with a happy smile.

The great grandson of Queen Elizabeth II and third-in- line to the British throne, beams out of the portrait taken at Kensington Palace in London ahead of his birthday, which the youngster will celebrate tomorrow.

Prince George Alexander Louis - known as His Royal Highness Prince George of Cambridge - was born on July 22, 2013.

"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," Kensington Palace said in a statement.

The prince spent the run-up to his big day on an official tour of Poland and Germany with his parents.

The photo was taken last month by Getty Images royal photographer Chris Jackson.

Jackson tweeted that he was honoured the Duke and Duchess of Cambridge released his photo.

"I'm thrilled and honoured that the Duke and Duchess of Cambridge have chosen to release this portrait to celebrate Prince George's fourth birthday. He is such a happy little boy and certainly injects some fun into a photoshoot," Jackson said.

In September, Prince George is due to start school. He will go to Thomas's Battersea, a private preparatory school located a few miles from the family residence in Kensington Palace in London, where the family will be based.