Singer Billie Eilish has opened up about her mental health struggle and how she harboured suicidal thoughts in 2018.

The Grammy nominee made the confession on "The Gayle King Grammy Special".

"I was so unhappy last year. I was so unhappy and I was so, like, joyless," Eilish said, reports aceshowbiz.com.

Shoe host King felt "fame had taken a heavy toll" on the 18-year-old superstar EIlish. "She couldn't go out in public without being recognized and most of her friends, unable to relate to Billie's new pop star status, had drifted away. Lonely and isolated, she fell into a clinical depression," King added.

In response, Eilish said: "I don't want to be dark, but I genuinely didn't think I would, like, make it to, like 17."

She then spoke of the time she was alone in a Berlin hotel room.

"I think about this one time I was in Berlin, and I was alone in my hotel, and I remember there was, like, a window right there. I, like, God, I remember crying because I was thinking about how the way that I was going to die was, I was going to do it," she said.

"I wanna end me," in her song titled "bury a friend," used to have a literal meaning.

You know, there's a lyric in one of your songs where you talk about the end of me. When I heard that, I thought, 'God, I wonder if Billie was talking about herself'," Gayle said.

"I was," Eilish replied.

The singer said she was doing better now, adding that she always encourages fans with a similar struggle in life not to give up.

"I just grab them by the shoulders, and I'm like, 'Please, take care of yourself, and be good to yourself and be nice to yourself. Don't take that extra step and hurt yourself further. You can't take it back," she said.