Prince George turns nine: New photo shows prince is the 'spitting image' of Prince William

Prince George is turning nine.

The future king is turning nine tomorrow, and to celebrate, the Duke and Duchess of Cambridge have released a new portrait.

The eldest son of Prince William and Kate looked just like his father in the handsome portrait as he wore a light blue polo shirt and flashed the camera a big grin.

Taken by the Duchess, the royals posted the photo to their social media accounts and captioned the post, "George is turning 9!", adding in a statement: "The Duke and Duchess of Cambridge are delighted to share a new photograph of Prince George ahead of his ninth birthday tomorrow".

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A post shared by Duke and Duchess of Cambridge (@dukeandduchessofcambridge)

Royal fans quickly took to the comments section of the Instagram post, with many pointing out how much the young prince resembles his father.

One said: "He's looking so much like his dad these days! Happy birthday George!", while another person commented: "Wow, a little William, spitting image".

Another royal fan couldn't believe how old he looked and said, "Gosh, where have those 9yrs gone! Happy birthday, kiddo!".

Kate has been known to get behind the camera to capture the perfect shot of her children for their birthday portraits in recent years.

Prince George pictured when he turned seven. Photo / Kensington Palace

She recently captured some adorable photos of Prince Louis for his fourth birthday with a joyful collection of photos showing the couple's youngest son playing in the sand, sprinting in front of the camera with a huge smile on his face and another showed him playfully holding a cricket ball.

The couple have made it a tradition to release new photos of their children for each one of their birthdays. Last year when George turned eight, the Duke and Duchess released a photo of him grinning from ear-to-ear wearing a navy and orange polo shirt and matching navy shorts.

The adorable photo appeared to be a touching tribute to the birthday boy's great-grandfather Prince Philip, as he was seen sitting on a Land Rover - which happened to be a favourite car of the late Prince.