The reason why Kate and William decided to share the final shot from Prince Louis' christening

Prince Louis might not even be three months old but he's already melting hearts all over the world.

The little royal was christened last week, and official pictures of the special event were released over the weekend.

However, the Cambridges decided to give us yet another glimpse of their new baby, and released an additional photograph of Louis with mum Kate - and, unsurprisingly, he looks adorable.

The snap was shared on the official Kensignton Palace Twitter account, with the caption: 'The Duke and Duchess of Cambridge have released an additional photograph taken following the christening of Prince Louis.

'The Duke and Duchess hope that everyone enjoys this lovely photograph of Prince Louis as much as they do', they added.

And it turns out that the snap was originally not meant to seen by the eyes of the public. While the official snaps were taken by photographer Matt Holyoak, the Cambridges also hired Matt Porteous to take some personal snaps of the day - for their family album, just like any normal family.

But as the snap of mum and son turned out to be so adorable, William and Kate decided to share it - and we're thankful they did!

Royal fans were quick to gush about how adorable Prince Louis looks alongside his mum Kate, with some saying they look 'perfect'.

One said: 'Sooooo cute !!!!! Probably smiling at his big brother and big sister!!! 😁', while another added: 'HE IS SO ADORABLE!!!!!!! 😍😍😍😍😍😍'.

A third wrote: 'Just adorable. The perfect mother and child photo that anyone would wish for on such an occasion.'.

A fourth also commented on the picture, adding that Kate looks glowing: 'OMG that is the cutest photograph.. Prince Louis is adorable. Doesn't Catherine look glowing..'.

The additional picture comes after the Cambridges shared a series of snaps of the special day, which was attended only by close family members and friends who were picked to be Prince Louis' godparents.

In one of the snaps, Princess Charlotte proves she's a doting big sister as she's seen holding Prince Louis’s hand and is fixated on her little brother.

The little royal is said to be really enjoying her new role as a big sister, as a source revealed to US Weekly recently: 'She is really enjoying having a younger brother to play with. She's taking her big sister duties very seriously. She won’t leave baby Louis’s side.

'Charlotte is just like [George]. They have a great bond, and a similar connection is growing between Charlotte and Louis.'