Rising Chicago-area rapper Jarad Anthony Higgins, known by the stage name Juice WRLD, died Sunday morning, the Cook County Medical Examiner's Office confirmed to NBC News.

Higgins, 21, hit No. 1 on the Billboard 200 albums chart this year with the studio album "Death Race for Love." He was signed to Interscope Records and was considered at the forefront of the emo rap scene.

The cause of death is unknown. Police say Higgins "suffered a medical emergency" early Sunday at Midway Airport in Chicago, NBC Chicago reported.

TMZ reported that Higgins had a seizure after a flight from California, although this hasn't been independently verified by NBC News.

Higgins, a native of the Chicago area, released a collaborative album in 2018 with Future before releasing his debut record, titled "Goodbye & Good Riddance."

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The album's title began trending on Twitter shortly after TMZ first reported the news of his death.

Higgins once rapped about the short lives of artists in his single "Legends," on which he said he didn't want to be known as a legend because "all the legends seem to die out."

"We keep on losing our legends to the cruel cold world," the lyrics said. "What is it coming to?"

Another lyric from the song, "What's the 27 Club? We ain't making it past 21," also made the rounds on social media as fans mourned.

Higgins grew up in the Calumet Park neighborhood of Cook County learning different instruments, including piano and guitar, before turning to freestyle rap in high school, according to his YouTube biography. His work was featured on the "Spiderman: Into the Spiderverse" movie soundtrack and the BTS: World mobile game soundtrack.

Other artists, such as Lil Yachty, Ellie Goulding and Kelhani, expressed sadness at the loss and memorialized the Higgins in social media posts Sunday. Goulding, who worked with Higgins on her song "Hate Me," wrote on Twitter that Higgins was "such a sweet soul."

"I'll always remember meeting you and your family on the video set and thinking how close you were," Goulding said. "You had so much further to go, you were just getting started. You'll be missed Juice."

DJ and producer Zedd, who is also signed to Interscope Records, tweeted that he was shocked.

"A reminder that life can be over any moment ... be kind to one another," he wrote.

CORRECTION (Dec. 8, 2019, 3:55 p.m. ET) : An earlier version of this article misidentified the author of condolences posted to Twitter under the name Ninja. It was written by Richard Tyler Blevins, a professional American gamer, not Watkin Tudor Jones, a South African rapper. The condolences have been removed.