The 24-year-old singer looked super cool in a black bow tie and white blouse while boyfriend Yungblud hit the red carpet separately from her.
Halsey and Yungblud are both set to take the stage for performances during the show.
Halsey is nominated for four awards tonight including Female Artist of the Year.
The iHeartRadio Music Awards airs tonight at 8pm ET on Fox.
FYI: Halsey is wearing a Dsquared2 outfit, Cult of Coquette heels, Anita Ko earrings, and a Yeprem ring.