The awesome reason why this woman's changing room selfie has gone viral

Most of us take a sneaky snap in the changing rooms when we're trying on something we want a second opinion on, but Rachel Taylor took her changing room selfie to a whole new level when she posted it to the Facebook page of the store she was in - and the story of why is brilliant.

Rachel was trying on some outfits in the changing rooms of Old Navy, a popular US clothing store, when she overheard a conversation that provoked a strong reaction in her.

'Old Navy, thank you for having adorable clothes for all shapes & sizes. I'd like to tell you the story behind this tank top and why I'll be rocking it tomorrow for July 4th,' she wrote on the company's Facebook page.

'Today I was shopping in Old Navy, standing in between a teenage girl and her mom. The girl picked up a plus-size tank top, showed it to her mom and said, "Look! Me and So-and-so can fit in this tank top!" Her mom laughed and said, "Yeah, you could! That thing is huge!"'

Image: Facebook/Rachel Taylor

Rachel wearing the tank top in question

'I couldn't help it; I started crying. I guess the girl and her mom walked away. I have no idea. My husband walked me out of the store to the car. I sat in the car crying for a long time but eventually went back inside to finish my shopping.'

'I ended up buying that tank top because, it turns out, I look fierce in it! Be kind. Think about others before you speak. And if someone hurts you, you have to move on.'

Since she shared her story on 4th July, Rachel's post has received more than 229,000 likes and 10,600 shares, and she's had thousands of supportive comments - including one from Old Navy themselves.

'Rachel, you are amazing. We want to celebrate your fierce style by sending you a gift card. Please keep an eye out for a message from us!' the brand wrote underneath her picture.

It's amazing what a simple story can turn into - we'll expect to see more fabulous selfies in your new purchases, Rachel!