Golovkin, who will also box July 26 at Madison Square Garden, made a cameo as a boxer in the Broadway musical, and announcer Buffer said his legendary "Let's get ready to rumble!" on stage to kick off the final fight scene in the production.
As previously reported, Rocky will end its run after 216 performances Aug. 17.
Rocky, according to press notes, "brings to life the iconic and inspiring story of struggling small time Philly boxer, Rocky Balboa, who gets a once-in-a-lifetime shot to go the distance against heavyweight champ Apollo Creed. Both an adrenaline-infused spectacle and a surprising story of blossoming romance between two lonely outsiders, Rocky is a heart-stopping and viscerally theatrical new musical for everyone brave enough to follow their dream."