The singer performed her hit song "Without Me" during the episode, which also marked her first time acting as the host of the long-running NBC variety sketch series. For her second performance, Halsey performed her collaboration with benny blanco and Khalid, "Eastside," as she painted a face on the stage.
Fans of the singer, who were already pleasantly surprised by her acting debut earlier in the episode, were proudly complimenting her singing chops.
"This stripped down version of "Without Me" is [clapping hands emojis]," one user said, praising the stripped down performance.
"I say it all the time, I'm not her target audience, but I am a huge Halsey fan. I think she's doing well tonight," another user commented.
"Hot damn, Halsey has a lovely, haunting voice. First time I've ever heard her sing live, but I'm a believer," a third fan commented.
Other SNL fans were not as kind to the "Bad At Love" singer, choosing to criticize her outfit and music as she carried on with her performance. Others also compared her to singer P!nk.
Angsty singer in her underwear on #SNL. Ho-hum.— Je Reviens (@2DreamIt) February 10, 2019
"I'm sorry but she reminds me too much of Pink! when she first came on the scene in 2000," one Twitter user said.
"Lip syncing, right? Also, has there been one laugh?" another user commented.
The singer's stage showed a massive mural that read: "Ashley, I Cheated" likely a reference to her much-talked-about breakup with rapper G-Eazy, who reportedly cheated on the singer leading to the end of their relationship at the end of summer 2018.
Halsey (whose real name is Ashley Nicorette Frangipane) celebrates her third time singing on the series at the same time as she joined a unique group of celebrities who have gotten to act as host and musical guest on the same episode.
Other Hollywood stars who have been tapped to pull double-duty on SNL include Justin Timberlake, Ariana Grande, Justin Bieber, Elton John, Lady Gaga and Drake.
Ahead of the episode, Halsey had been keeping spirits high on her social media teasing the episode, writing on Twitter Friday: "Tomorrow is gonna be so wow."
"Without Me" marks the singers first single to land in the No. 1 spot on the Billboard Hot 100 in the United States. The singer and Ariana Grande spent several weeks sharing the No. 1 and No. 2 spots on the charts since the release of the Grande's hit singles "Thank U, Next" and "7 Rings."
Saturday Night Live airs weekly at 11:30 p.m. ET on NBC. The next episode will air Feb. 17 and feature Avengers and Black Monday star Don Cheadle as host and singer Gary Clark Jr. as the musical guest.