ET's Keltie Knight sat down with the "Bad Guy" singer at the GRAMMY Museum in Los Angeles ahead of her intimate show and fan Q&A, where she also dished on her upcoming and "terrifying" performance on Saturday Night Live, turning 18 and what winning a GRAMMY would mean to her.
Eilish is in contention to be nominated for the big four awards at the GRAMMYs -- Album of the Year, Song of the Year, Record of the Year and Best New Artist -- the youngest woman ever to do that.
"Is that true?" she asked. "I still haven't thought about it. I don't think I'll be on stage, you know? I think it's so weird when people think they're going to be huge. God, that's so weird. I never in a million years would have thought this sh*t would happen. I'm only grateful for it, for real."
Eilish has had nothing but success come her way since stepping out on the scene. Fans are obsessed with the songwriter because of her edgy music, unique sense of style and how real she is. While she and brother Finneas have had many great moments together, come December, Eilish will be celebrating another major milestone: her 18th birthday.
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"Eighteen has been, like, the age I've always wanted to be my entire life and here it is," she expressed, adding that she has "something in mind" for how she's going to celebrate.
Meanwhile, come Sept. 28, the singer will serve as the musical guest on the SNL season premiere.
"I'm so excited," she said about her upcoming gig. "TV performances are like a completely different world. It's so terrifying and so [exciting]. The experiences I've have had always been good, so I'm looking forward to it."
As for performing at the GRAMMY Museum with her brother, Finneas, the "Lovely" singer shared that it was "so much fun."
"I used to come here all the time when I was younger," Eilish said. "I saw lots of shows on this stage, in this room, so it was weird to just now be walking in and this is the situation. It's super weird because I came here my entire childhood. I saw so many artists here. It was so much fun."
ET also caught up with Finneas at the event, where he opened up about how easy it is to work with his sister. Watch below to hear what he said.