Ulrich was speaking to MTV News in the UK about Metallica's new movie "Through the Never" when he made the revelation, but fans shouldn't hold their breath waiting for it to happen.

"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." Ulrich said. "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."