Dave Grohl explains how Taylor Swift saved a performance for him while he was 'super high'

Dave Grohl has his fair share of party stories, and not everything always goes as planned.

During an acoustic performance at the Cannes Lions festival, the Foo Fighters' frontman told a story about the time he was at a party with Paul McCartney and Taylor Swift.

McCartney, whom he calls "the baddest motherf---er in the world," began to play a new song for the party guests. Everybody loved it, so when McCartney was done, they asked Grohl to play a song.

Grohl's first thought was, "Well, I don't know how to play piano. Like, I don't know what to do, man. I can't play f---ing piano."

He couldn't even play any of McCartney's guitars, because McCartney is left-handed. He was also faced with another dilemma.

"And also, I'd maybe smoked a little pot, so I was already challenged enough," he recalled.

But as Grohl struggled with what to do, Swift stood up and offered to play "like f---ing Batman when you need him."

Grohl then picked up one of McCartney's bass guitars and tried to play along with Swift while he was "super high." He quickly realized that the "really beautiful thing" Swift was playing was the Foo Fighters' "Best of You."

"As if I weren't high enough, that f---ing blew me into outer space, man," Grohl said. "I felt obligated to sit next to her and duet."

You can listen to Grohl tell the story and play "Best of You" below: