The drummer was impressed with the Poker Face star's rendition of Moth into Flame during the awards show, and recently suggested she should become an honorary bandmate.

He now tells The A.V. Club, "I knew this was going to work. I mean, Gaga is a metal chick at heart. There was no way this was not going to work. It was totally in her DNA. It was totally in her wheelhouse... The only question was at what level it was going to work.

"We did one run-through. The way her and James' (Hetfield) voices worked, it jelled so well together we all kind of stood there like, 'Huh?' It was really f**king next-level. I think we rehearsed it twice, maybe three times on Friday night. And it was just dialed in. There was no sort of, 'Oh, my God, what are we doing here?' This was as natural and organic as you could imagine this type of stuff being. This was a home run from the get-go."

And now he hopes what initially seemed to be an odd Grammys match-up will become a long-term commitment for the pop star and the metal band.

"As you spend 72 hours with somebody, and there's this connection and this intimacy, part of it is that maybe you don't want it to end," Ulrich explains. "When these moments work, you always leave them open to reconnection.

"Obviously, we're not sitting in a recording studio today writing songs for a record or anything. I think that our weekend together was so seamless and so authentic and such a natural fit that the idea of revisiting this at some point down the road (is a good one).

"As we were walking off one of the sound checks, she said to me, 'We gotta do something again together. This is just too good to leave'. And I said, 'I agree with you. It's just too real'.

"Obviously, we haven't sat around and talked about this yet. But if there was ever an opportunity to revisit something like this, this is about as pure as it could get. So we'll see."