The 17-year-old musician, who regularly speaks out about animal-rights and veganism, was asked 'What's a positive thing in the news right now?' in Vanity Fair's Billie Eilish: Same Interview, The Third Year.
'Our time is running out'
"Greta Thunberg, honestly," Eilish responded. "She's been f***ing kicking people's ass."
The Bad Guy star has previously shown support for the Global Climate Strike - spearheaded by 16-year-old Thunberg - writing to her then 38.6 million Instagram followers: "TICK TOCK! Our time is running out. The climate crisis is very real. We need to speak up and demand that our leaders take action."
'No Music On A Dead Planet'
Eilish recently donned a t-shirt reading 'No Music On A Dead Planet' to the American Music Awards (AMAs) - where she scooped six nominations and two awards for New Artist and Artist Alternative Rock.
The slogan was coined by Music Declares Emergency - a group of 'individuals and organizations within the music industry declaring a climate and ecological emergency'.