Heavy metal band Metallica announced Monday morning that six shows were being added to their upcoming Sphere residency after "unbelievable" demand.

After months of rumors, Metallica finally made the announcement fans were waiting for last week: a residency at the Sphere. But when do tickets go on sale?

So... Metallica wants you to know something BIG is happening Monday. They're just not saying what yet.

The group is currently touring in Asia, but will be stateside Sunday for the Grammys, where they'll perform with Lady Gaga.