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Lady Gaga Was Basically Like 'YAASSS' At AC/DC's Grammys Performance

Even Katy Perry was throwing up devil horns.

While AC/DC's opening performance of "Highway To Hell" and "Rock Or Bust" at the 57th Annual Grammy Awards might have left Pharrell wondering how the hell he managed to wear the same outfit as Angus Young, it left Lady Gaga shaking and crying in a classic-rock case of emotion.

If given the choice between "Rock Or Bust," Lady Gaga chooses "YAAAAAAAAAAAASSSS."

CBS/MTV

Katy Perry was feeling AC/DC's performance, too.

CBS/MTV

\m/(-_-)\m/ \m/(-_-)\m/ \m/(-_-)\m/ \m/(-_-)\m/ \m/(-_-)\m/

CBS/MTV

Oh my god, don't even get Dave Grohl STARTED.