Metallica fans are about to choose the band's best song ever.
The band has been hosting a bracket-style tournament on its Instagram page over the last month, starting with 64 songs that have been whittled down to just two.
Now, "Master Of Puppets" and "One" are facing off in the 'Some Kind Of Bracket' finals - after holding off 'Fade To Black' and 'Enter Sandman' in the semis.
You can vote on the band's Facebook and Instagram pages, but hurry up - voting ends soon.