Princess Mary's sweet moment with son Christian at Queen’s birthday celebration

Crown Princess Mary of Denmark has shared a sweet moment with oldest son, Prince Christian, at the 78th birthday celebration of Queen Margrethe.

At the queen's first public appearance since the death of husband Prince Henrik earlier this year, the family smiled and waved to the awaiting crowd.

Read more: Princess Mary in pictures

Dressed in a vibrant red frock, Princess Mary was openly affectionate with each of her four children.

And at one stage, she and Prince Christian shared a private joke, laughing openly with each other.

Crown Princess Mary, 46, appeared with Queen Margrethe and her four children - Christian, 12, Josephine, 10, and twins Vincent and Josephine, seven.

Crown Prince Frederik was unable to attend due to a trip to Greenland.

The royal family regularly share special moments together, with the siblings fondly displaying their affection for one another.

Prince Christian of Denmark is 12 and is now second in line to the Danish throne after dad, Prince Frederik.

While the young royal doesn't undertake official duties, he does attend family events under the careful watch of his proud mum.

At a more recent appearance, Crown Princess Mary of Denmark made a solo appearance, opening a new hospital in Slagelse.

She was pretty in pink, dressed by local label Elise Gug in a pale pink skirt, white blouse and snakeskin heels by Gianvito Rossi.

She cut the red ribbon and declared the hospital officially open.