The "Good Looking" singer also shared a backstage photo she snapped with the pop star.
"I would like to dedicate this next song to Mr. Waterhouse,” she said before performing 2008's "Decode."
The curiously capitalized bonus track is part of two new limited-edition The Tortured Poets Department acoustic digital collections.
The K-pop idol saw the pop star's blockbuster concert in Singapore earlier this year.
It's a cruel summer, indeed.
The stop was canceled after authorities discovered a terror plot targeting the concerts.
Paramore is also still on board for all five nights in London.
The rapper featured a reference to the singer's romance with Travis Kelce on his new album.
"You guys are seriously so creative," the pop star raved.
