The incident happened during the guitar-solo section in the song "Moth Into Flame".Kirk was soloing away with his right foot on the guitar effects pedal board when he slipped and fell backwards, hitting the ground with his feet high above his head. After taking a second to laugh about the stage mishap,Hammett picked himself up and continued playing the song.
Keeping with his good-natured spirit, Hammett posted the video of his fall from two different angles and included the following caption: "Ummm- I slipped on my wet wah pedal. It rained so much I felt like I was playing guitar in the shower - #slipperywhenwet #wahwahwah #metallicafamily #Metinmilan @metallica"