The 22-year-old former 5th overall draft pick was sitting in the team's hot tub (hey, gotta take care of the body) minding his business, listening to Hozier's hit single when his teammate Darius Garland walked in.

While the music was blasting, Garland started singing the chorus, and that's when Okoro got up and put on a show.

"Offer me that deathless death, Good God, let me give you my life, Take me to church!" the two belted out.

Okoro's choreography was on point with a hilarious backward fall into the hot tub to conclude his performance .. and Garland couldn't help but laugh.

Of course, Okoro and Garland have a lot to be happy about ... they just whooped the Los Angeles Clippers 122-99 on Sunday. The Cavs are currently ranked 5th in the Eastern Conference.

Plus, Garland -- who signed a five-year deal worth $231 million last season -- is averaging 21.9 points and 8.2 assists per game.

BTW, the song might ring a bell for Cavs fans ... it's the track that was playing in LeBron James' Beats by Dre commercial when he returned to Cleveland.