Halsey "Lucky to Be Alive" Amid Health Battle

And while Halsey may have kept the specifics of her diagnoses and treatment private, "The End" does provide an intimate look into her struggles.

"Every couple of years now, a doctor says I'm sick," she sings in the song's opening line. "And at first, it was my brain, then a skeleton in pain / And I don't like to complain, but I'm saying sorry."

Halsey—who confirmed her relationship with Avan Jogia in October—then continues, "When I met you, I thought I was damaged goods / Had a f--ked up childhood / And there's poison in my brain and in my blood."

"When I met you, I said I would never die / But the joke was always mine 'cause I'm racing against time," she sings in the final verse. "And I know it's not the end of the world, but could you pick me up at 8? / 'Cause my treatment starts today."

Halsey's emotional song and health news come shortly after she fiercely defended Kate Middleton amid the scrutiny on the Princess of Wales' retreat from the public eye, which she eventually shared in March was due to a cancer diagnosis. 

"Hope the people and the media who sensationalized a woman's desire for privacy following a known health incident are experiencing regret and remorse," Halsey wrote in an Instagram Story March 23. "And by the way, that would stand even without the terrible news of her journey."

The "Without Me" singer also expressed her belief that even those living in the spotlight are entitled to their privacy. 

"I understand when you have a public life certain things like this can get out of hand," she continued. "But god forbid someone needs a break for a few weeks or months, it's no one's business why. And with respect to public life, who you are and how you're doing when you ‘sign up for this' is subject to change at any moment. And the newly changed ‘you' in place (for whatever amount of time; days weeks years) may not have the same stamina or tolerance."