A young mum wrote a 'thank you' note to her ex's new girlfriend. It's going viral for all the right reasons.

We’ve heard the tales about evil stepmothers.Cinderella had one, Hansel and Gretel did too. Snow White had the meanest of them all.

They set the tone for the assumption that step mothers are bad news.

Well, no.

And one mum’s public acknowledgment of the contribution her daughter’s step-mother makes is doing wonders to change that perception.

Audrey Loving, a young mum from Virginia in the US, paid tribute to her former partner’s new girlfriend in a Facebook post that has since gone viral, being shared nearly 150,000 times.

She says her “daughter’s father’s girlfriend” is “the sweetest thing ever”. She says she is eternally grateful of the way she “basically takes care of her daughter like she is “her own.”

It’s an unusual relationship between two women who probably shouldn’t get on, if stereotypes are anything to go off.

Audrey Loving, split from her former partner, Corey Henry, several years ago and the two now live in separate states.

Their daughter, Riley, 4, lives with her mum, but her dad remains involved in her life and often takes her on weekends.

Loving told Today that when her former partner found new love she was determined not to be bitter.

“I come from a blended family — I have stepsisters, half-sisters,” she said. “Growing up, I heard the negative talk about the ‘other woman,’ and I didn’t want my kid to hear the same thing … It’s not fair. Kids are smart.”

She said she also felt for the newcomer, Whitney McGraw, taking on the responsibility of a child who wasn’t her own.

“It’s awkward for her too — dating someone with a kid,” she said. “I’m not interested in the baby mama drama … I welcomed her into my family with open arms.”

And her viral Facebook post shows it.

She wrote:

“I'm super thankful for her because when she visits her dad she feeds her, takes care of her, buys her gifts, and basically takes care of her like her own.”

She continued: “why do all these moms act so spiteful and jealous towards the other women? NOONE said it was easy trying to be a mother to a kid you didn't have. So when there is someone trying, don't push them away! Because they DON'T need the drama they WILL leave and then you're stuck with someone who is the evil step mom.”

Loving said that the evil step mother does exist.

“Yes they exist! I see them everywhere!”

But she says it is possible to co-exist in harmony.

“A kid can have two moms because in my eyes the more people that love her I'm happy! I would never make her feel like an outsider; I'm extremely thankful for this girl.”

She ends by pleading for other women to take a similar stance, for the sake of their kids.

“Ladies, grow up and focus on being a good mom. Love more hate less!"

Loving says she wasn’t always so easy going and when Riley first began spending time alone with the couple, she would pester them with messages.

“I would write a whole list for Whitney. Things like, ‘Don’t leave her in the bathroom,’” she said.

“Whitney would send me pictures and keep me updated," she recalled. "One night I sent her a text saying, ‘You know, I’m extremely thankful for you.’”

She acknowledges that it’s not always easy, but still she says it’s up to grown-ups to lead the way.

“Of course it’s hard,” Loving said.

“You have a kid and your mama bear comes out. But the fact that someone’s there loving my daughter … I’m at peace knowing she’s being taken care of. The more people that love your kid, the better.”