The longtime friends will be hitting the road together in May for the remaining international dates on Swift's blockbuster tour.
Williams is recalling her unlikely introduction to Swift years ago.
The singer says she's working on new music ahead of the band's upcoming opening slot on Taylor Swift's Eras Tour in Europe.
The songstress took to Instagram to reveal that she's still battling her illness and cannot perform the last two dates of their tour.
Billie Eilish gushes over performing with a childhood hero, Hayley Williams of Paramore, in a tribute on Instagram.
Eilish called the surprise performance a 'dream come true.'
The singer revealed the tracklists and features that will appear on the forthcoming album, out July 7.
Check out some of ET's top new music picks of the week!
The bandmates have disclosed no further details about their relationship.
Billie Eilish made fans 'happier than ever' at Coachella 2022 weekend 2, with surprise guest Hayley Williams of Paramore!
The Paramore frontwoman joined Billie Eilish for the second weekend of Coachella.
The singer and Chad Gilbert called it quits in 2017.
ET sat down with the band's frontwoman at Beautycon Festival LA over the weekend.
Hayley Williams and hair artist Brian O'Connor spoke with ET about their company Good Dye Young as well as what's next for her band.