The heavy rockers were the main event at a surprise party for tech company Saleforce's CEO Marc Benioff, and the whole set was caught on film.

Metallica played hit tracks such as Enter Sandman, Master of Puppets and Seek and Destroy, and now they're giving fans the opportunity to download footage of the gig in its entirety on their site

The odd collaboration between the band and the tech company bosses isn't completely unexpected - Benioff is guitarist Kirk Hammett's neighbour.