Kate and William release adorable portrait of the Prince as they prepare to celebrate his birthday at home after a helicopter ride treat on their whirlwind royal tour

On the eve of Prince George's fourth birthday, his parents have released an adorable portrait of their son taken by royal photographer Chris Jackson at Kensington Palace, in which he flashes a cheeky, gap-toothed grin for the camera. George and his little sister Princess Charlotte joined Kate and William on their royal tour of Europe this week, but the family will celebrate the Prince's birthday in private at home in the UK on Saturday. As an early birthday treat, the young royal was treated to a sneak peek inside a helicopter ahead of the family's return flight on Friday afternoon. Kensington Palace said in a statement: 'The Duke and Duchess of Cambridge are delighted to share a new official portrait of Prince George to mark His Royal Highness's fourth birthday tomorrow.'