When kids first discover that Santa does not exist, their first instinct is often to tell their friends. But when a little boy in the US did just that, his little friends’ parents weren’t impressed – and now, they are threatening to sue his mum.

Yes, seriously.

Within days of her Year 1 son “ ruining Christmas “, the mum received a letter from a law firm outlining the parents’ intention to sue her for “emotional damage, flagrant disregard to parental rights, and facilitating the loss of innocence of child wonderment”.

The boy's distressed mum took to Reddit to share her story.

She described how the parents (who she describes as "know it all, PTA, suburban Stepford Wives") demand that her son stay away from the children he apparently "traumatised".

But wait - it gets worse. Just have a read:

The single mother writes that she can't afford a lawyer or to pay for a fully interactive " Santa Experience".

We're speechless - and we just hope the other parents have enough sense to grow up and leave this family alone.

Has your child discovered that Santa isn't real yet? How did you handle it?

TAP on the image below and scroll through the gallery to see a round-up of our favourite Christmas movies…

Classic Christmas Movies.

Bad Santa.

Elf.

Home Alone.

It's A Wonderful Life.

Jingle All The Way.

Love Actually.

National Lampoon's Christmas Vacation.

Polar Express.

Scrooged.

The Holiday.

The Miracle On 34th St.

The Muppet Christmas Carol.

The Santa Clause.