Cristala Poole told ABC13 that she recently encountered a man named Maurice near a McDonald's restaurant in downtown Houston. Poole was on a mission to do 35 random acts of kindness for her 35th birthday.
In a video, she explains to Maurice why she decided to treat him as part of her way of paying it forward.
Little did she know that her birthday mission would turn into much more than gesture from her.
Watch the video above to see the sweet serenade happen.
Poole was so touched by the rendition that she is hoping to find Maurice again.
WATCH: Extended video of the sweet serenade