After walking the red carpet in head-to-toe Burberry, the 17-year-old singer took the stage at the Microsoft Theater in Los Angeles, for her first-ever awards show performance.
Following a hilarious introduction from Tyler the Creator, Eilish -- rocking space buns and an oversized T-shirt emblazoned with sparkly red flames -- certainly didn't hold back, pumping up the crowd to a fiery hot performance of "All the Good Girls Go to Hell."
The performance was well-received by stars in the audience (like Lil Nas X, who got a close-up!), as well as fans on social media.
It's been a great week for Eilish, who made history on Wednesday for completing the GRAMMYs Grand Slam along with Lizzo. The powerhouse females were nominated in the four biggest categories (Album of the Year, Song of the Year, Record of the Year and Best New Artist), a feat two artists have never been able to do in the same year.
Speaking with ET back in September, the "Bad Guy" singer opened up about another upcoming milestone she'll celebrate before 2019 is over -- turning 18 on Dec. 18!
"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 ring in her special day. Hear more in the video below.