Billie Eilish is opening up about her two-month battle with COVID-19.

In an interview with Howard Stern on Monday, the singer revealed that she’d contracted the virus in August, explaining she was sick for nearly two months and that she still feels the side effects to this day.

“F*** that s**t, dude,” she told Stern of the experience, later adding that the whole thing was “miserable.”

Eilish had not previously shared her COVID-19 diagnosis publicly.

“It was bad,” she said. “I mean, I didn’t die and I wasn’t going to die, but that does not take away from how miserable it was. I mean, it was terrible. I still have side effects. I was sick for, like, two months almost.”

The “Happier Than Ever” singer, 19, also clarified to her fans that the COVID vaccine saved her life.

“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. When I say it was bad, I mean that it felt horrible, but really in the scheme of COVID, it was not bad. You know what I mean?

“When you’re sick, it feels fucking horrible,” she explained. “When you have a cold, you know, I have a cold right now. When you have the flu, it feels like you’re dying when you’re OK. So when I say it’s bad it’s not like it’s, oh my God I was gonna die of COVID and the vaccine doesn’t work. The vaccine is fucking amazing. And it also saved [brother and collaborator] Finneas from getting it, it saved my parents from getting it, saved my friends from getting it.”

The singer, who recently earned seven nominations ahead of the 2022 Grammy Awards, has much to look forward to in the new year.

Eilish’s message comes at a time when COVID cases are spiking across the country and the Omicron variant is on the rise in the U.S. According to CDC data, over 70 percent of the adult population in the U.S. is fully vaccinated.