A young woman's simple act of kindness has turned into a blossoming friendship between her and a depressed stranger who needed a pick-me-up.

Mackenzie Mauller was at a Starbucks in Ohio earlier this week when she spontaneously decided to pay for the order of the woman behind her in line.

When she left the store, she didn't think much of her good deed. Later that day, however, she found a heartfelt letter in her mailbox.

The letter was from Nicole Clawson, a woman who had fallen on hard times and incidentally lived right next to Mauller.

"Thank you for the coffee!" Clawson wrote in the letter. "I rarely go to Starbucks and treat myself, but the last couple of months have been a bit of a struggle.

"My father just passed away and he was also my babysitter. My family and my children have had a really hard time. This morning, my babysitter called off sick and I had to take the day off work. I decided to buy my kids breakfast and get myself a coffee with total guilt because I am going to be a stay-at-home-mom for a while.

"Since I was not planning to go this route in my life, I was not emotionally and financially prepared to quit working. I cried when I found out you were so sweet to buy my coffee."

Not only that, Clawson said that she was then "thrilled" to see Mauller pull into a driveway that was a few houses down from her own – so she penned up the sweet note and left it in the mailbox.

"I felt it necessary for you to know that what you did for me was more than just a coffee," she added. "It was something that has turned my whole day around, put tears in my eyes and a smile on my face."

Yesterday I bought coffee for the lady behind me at Starbucks.. later in the day I found this is my mailbox. Small acts can make a big difference folks, spread some kindness. pic.twitter.com/awNi4LSGJq

— Mackenzie (@mackey2399) August 7, 2018

Yesterday I bought coffee for the lady behind me at Starbucks.. later in the day I found this is my mailbox. Small acts can make a big difference folks, spread some kindness. pic.twitter.com/awNi4LSGJq

Mauller posted photos of the noted to Twitter where it has since garnered thousands of likes and retweets. She then penned a heartfelt card of her own and brought it to Clawson's house along with an offer to babysit.

Clawson was so overwhelmed – and delighted – by the young woman's kindness, she created a Twitter account so she could praise Mauller for her generosity.

"This has been such a great learning opportunity for [my children] on how to treat others, no matter what," wrote Clawson. "They are excited to pay it forward, and treat others with kindness and selflessness."

Pass On The Positive Story To Your Friends And Share To Social Media – Representative photo by Nick_Humphries, CC