Her little prince is growing up fast! Princess Mary's son Christian poses with his dog Ziggy in new portraits to celebrate his 10th birthday

  • Christian was born on October 15, 2005 at Copenhagen University Hospital
  • He is the eldest child of Australian-born Princess Mary and Prince Frederik
  • Christian, who is second-in-line to the throne, celebrated his 10th birthday
  • The occasion was marked with new portraits of the young royal
  • With blue eyes and chestnut hair, Christian resembles his father   

When Prince Christian was born ten years ago, bonfires were lit in celebration across Denmark and Australia as a 21-gun salute resonated through the streets of Copenhagen.

The young royal was the first child of Crown Princess Mary and her husband Frederik, the Crown Prince of Denmark.

Australian-born Mary has won the heart's of Denmark's people, and this month her first-born and second-in-line to the Danish throne celebrated his 10th birthday.

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A royal milestone: Prince Christian celebrated his 10th birthday on October 15 

A royal milestone: Prince Christian celebrated his 10th birthday on October 15 

Like father like son: New portraits of the young royal show he has followed in his father's footsteps in more ways than one as he is the spitting image of Prince Frederik

Like father like son: New portraits of the young royal show he has followed in his father's footsteps in more ways than one as he is the spitting image of Prince Frederik

Prince Christian Valdemar Henri John celebrated his milestone birthday on October 15.

A new series of portraits, released for the occasion, show Christian has followed in his father's footsteps in more ways than one.

His soft blue eyes and cleft chin make him the spitting image of the Crown Prince, who celebrated his 47th birthday on May 26.

Future king: Prince Christian is second-in-line to the Danish throne and the eldest child of Princess Mary and Prince Frederik 

Future king: Prince Christian is second-in-line to the Danish throne and the eldest child of Princess Mary and Prince Frederik 

Growing up: When Prince Christian was born, celebratory bonfires were lit in Denmark and Australia and a 21-gun salute resonated through Copenhagen

Growing up: When Prince Christian was born, celebratory bonfires were lit in Denmark and Australia and a 21-gun salute resonated through Copenhagen

Prince Christian was born in 2005 at Rigshospitalet, or the Copenhagen University Hospital.

He was christened in Christiansborg Palace Chapel on January 21, 2006, and grew up in the public eye.

His position as an only child was not to last, as Mary and Fred went on to have three other children: Princess Isabella in 2007 and twins Prince Vincent and Princess Josephine in 2011. 

A mother's love: Princess Mary holds Prince Christian at his christening in Christiansborg Palace Chapel on January 21, 2006

A mother's love: Princess Mary holds Prince Christian at his christening in Christiansborg Palace Chapel on January 21, 2006

Happy baby: Prince Christian breaks in to a cheeky smile at 10 months old 

Happy baby: Prince Christian breaks in to a cheeky smile at 10 months old 

Big day: Prince Christian of Denmark's first day at the Dronning Louises Bornehus nursery school

Big day: Prince Christian of Denmark's first day at the Dronning Louises Bornehus nursery school

Proud moment: Crown Prince Frederik and Crown Princess Mary take Prince Christian to his first day of school in August 2011

Proud moment: Crown Prince Frederik and Crown Princess Mary take Prince Christian to his first day of school in August 2011

The new portraits of  Prince Christian show the young royal dressed in a navy blue suit with a soft blue shirt casually unbuttoned beneath.

The second set of images show him casually dressed in green pants, a black jumper and brown sneakers on his feet.

Christian posed alongside his childhood companion Ziggy, the Danish-born Border Collie who was gifted to Mary and Fred in 2005 by the Danish Kennel Club. 

Stepping up: Prince Christian unveiled a portrait at Rosenborg Castle in November 2010

Stepping up: Prince Christian unveiled a portrait at Rosenborg Castle in November 2010

Birthday celebrations: Princess Mary and Prince Christian attend Queen Margrethe II 75th birthday celebrations at Amalienborg Palace in April 2015

Birthday celebrations: Princess Mary and Prince Christian attend Queen Margrethe II 75th birthday celebrations at Amalienborg Palace in April 2015

A family affair: Crown Prince Frederik and Crown Princess Mary walk with their son, Prince Christian 

A family affair: Crown Prince Frederik and Crown Princess Mary walk with their son, Prince Christian 

Eldest of four: Prince Christian has three younger sibling: Princess Isabella and twins Prince Vincent and Princess Josephine 

Eldest of four: Prince Christian has three younger sibling: Princess Isabella and twins Prince Vincent and Princess Josephine 

With his deep blue eyes and chestnut-coloured hair, Christian's resemblance to his father Frederik is striking.

Since 2011, Christian has attended Trane Overgaard School in Gentofte, Denmark.  

Despite his royal status, Prince Christian attended a public school to give him a 'normal' upbringing.

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