I want it to be clear that it is because of the vaccine that I'm fine," she said. "I think if I weren't vaccinated, I would have died, because it was bad."
Eilish is returning to Aotearoa for a tour date next year, and spoke about the Covid-19 vaccine to ZM's Fletch, Vaughan and Megan.
When asked what she'd tell Kiwi fans who haven't yet had the Covid-19 vaccine, she gave a simple answer.
"Gosh, just get vaccinated," she said.
And in her annual interview with Vanity Fair, she reminded her fans getting vaccinated was "not just for you ... it's for everyone around you. Take care of the people around you man."
Eilish hosted and appeared as the musical guest on Saturday Night Live over the weekend, and poked fun at her family during her time as guest host.
Despite pointing out her lack of acting talent in the opening monologue, by all accounts Eilish nailed her time as the show's guest.
She decided to dress as "Mrs Claus going to the club".
She also joked about her style choices, with include wearing baggy clothes.
"It wasn't just for comfort or for style. This is hard to say for me, but the real reason I started wearing oversized clothes back then is because I was actually two kids stacked on top of each other trying to sneak into an R-rated movie," Eilish explained.