The letter's author then followed up with three points, the first being: "Turn it the f**k up. I'm not joking. You play good s**t!"
His second request was for Cao to "tell me what songs you're playing" as "I need that s**t for my playlist".
Finally the letter ended with Todd stressing he "wasn't being ironic or anything" and to "send me some songs!".
"I've really enjoyed the music you've played since (you) moved in," he wrote. "No joke – good music!"
Cao's tweet has since gone viral, getting over 492,000 likes and countless replies from people who labelled it "the best neighbour note I've ever seen".
"Wish my neighbours were like this when I was younger," one person tweeted. "I was in a metal band with my friend and we would practice at my parents house and every time we did without hesitation the cops would show up they even complimented us after showing up so many times lol."
Others admitted to also being fans of their neighbour's music choices, with another tweeting: "One time I shazamed a song through the floor of my apartment bc I liked what my downstairs neighbour was playing."
Others called on Cao to share his music, prompting him to create a Spotify playlist "inspired by Todd and dedicated to all the chill neighbours out there".