Billie Eilish 'had a full-body reaction' to hosting 'SNL': 'I cried every single day of the week'

Billie Eilish appeared to slay Saturday Night Live with ease last Saturday (Dec. 11), but there were several points leading up to the big night when she didn't think she would be able to pull it off.

"Preparing for SNL is f—king nuts, dude," Eilish, 19, explained on Monday's (Dec. 13) The Howard Stern Show. "It's literally alien. I mean, I cried every single day of the week. No joke at all."

Stern asked if the tears came from insecurity over acting comedically.

"Yeah," the seven-time Grammy winner said. "I did actually love to act when I was a kid, but that's not my world, so I don't know what the f—k I'm doing. I feel like I am terrible. I feel like I suck. The craziest part of the week was I think it was Wednesday: the table read, where everybody reads ... a lot of scripts at a table."

Eilish revealed she cried in the green room during breaks from the table read. 

"I was just scared!" she continued. "It's SNL. These amazingly talented actors surrounding a table where somehow I'm the main course for this show. I didn't feel qualified for [it]."

It didn't stop at crying, though. Eilish admitted she threw up from the nerves: "Dude, I had a full-body reaction to being anxious about the whole week. I mean, threw up on the plane coming here. Had crazy s—ts when I got here. Like, you would not believe. You know the ones where you have to get fully naked on the toilet? [Laughs] I'm dead serious. I literally did."