A student who was preparing to graduate school sent out invites to her family in the hope they would be able to attend on the day.
It wasn't until a card dropped back through the door in reply that she realised she had sent one to the wrong address - and the message inside is restoring people's faith in humanity.
The card politely informed her that her family members no longer live at the address, and the new occupant took the time to congratulate the student for her achievements - even enclosing $20 (£14) inside as a gift.
The stranger's heartwarming act was posted on Reddit, where the recipient said: 'Accidentally sent a grad invite to my extended family's old address. Received this touching letter (and $20!) in return!'
It reads: 'Regretfully I must inform you that [her relatives] are not located at this address. I bought this house in September and am not acquainted with the prior owners.
'I unknowingly opened the envelope addressed to them by mistake and am returning the contents to you.
'That being said, I offer my congratulations! My niece attends [redacted] college of engineering. Though I don't know you, I am proud of you for pursuing a career in a STEM field (science, technology, engineering and mathematics).
'Us women have a lot of work to do to take our place in science and I am happy you are joining our ranks.
'I am a 35 year old mom of two, and didn't want to pass up the opportunity to wish you well. You are going to do great!'
The image of the card has gained hundreds of comments as people were left blown away by the heartwarming act. One said: "Brought a smile to my face. What a wonderful and kind gesture from a stranger."
A second said: "Some humans are absolutely fabulous."
And another joked: "Anyone else read this with a kindly old lady's voice in their head until they saw 35 and have a little crisis as this imagined grandmother faded away? No? Only me then."
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