Could Metallica, Green Day and U2 join forces for one massive tour together? If Metallica drummer Lars Ulrich has any say in the matter, it could happen. Speaking with MTV News in the U.K., Ulrich said, "U2 came to San Francisco two summers ago and we ended up having a lot to drink with them and Green Day following a dinner. I was told in the wee morning hours following this outing that members of U2, Green Day and Metallica agreed to tour together. We haven't talked about it since, but speaking for myself I'd be very up for that."

While the logistics of getting three huge bands together on one bill might be too much of a headache, a festival scenario is always a possibility, which is why Ulrich added that he would love for Metallica to play the U.K.'s legendary Glastonbury event one day.

Ulrich explained, "We've been fortunate enough to play every other festival on this planet numerous times, so Glastonbury is the only one that's eluding us. There's such a vibe and it's maybe the most quintessentially English festival."

Ulrich was in England to promote the release there of Metallica's IMAX concert movie, Metallica Through The Never, which has taken in just $3.2 million at the box office in three weeks of release in the U.S.

Metallica is slated to begin work on a new album sometime in early 2014, while U2 is reportedly in the final stages of work on its latest studio effort and is planning to release it early next year.