Nicole Scherzinger opens up about battling bulimia in an interview with British Cosmopolitan Credit: James White/Cosmopolitan

Nicole Scherzinger exudes major confidence while on stage, but the former Pussycat Dolls singer admits she was once "miserable inside" while struggling with bulimia. In a candid interview with British Cosmopolitan's August 2014 issue, the star opens up about that "dark time" in her life.

"I had such a great life on the outside, the Dolls were on top of the world, but I was miserable on the inside," the 36-year-old told the mag of how she spent her seven-year stint with the group during her twenties.

"It is such a horrible, paralyzing disease and it was such a dark time for me," the songstress said of her past struggle with bulimia, which she first went public with in 2012. "I didn't think anyone knew in my group or in my family because I hid it that well, I was so ashamed. I knew it wasn't normal or healthy because I was hurting myself through this cycle of disordered eating."

Scherzinger, who stuns on the cover in an all-denim ensemble, goes on to tell the mag she didn't confront her problem until she physically passed out on tour.

"I had started losing my voice, I couldn't sing at shows, and then I remember my manager finding me passed out on the floor in Malta or in the south of France," she recalled. "I thought, 'I'm going to lose everything I love if I don't love myself' … I’m never letting that happen again; you only get one life—I was 27 only once."

These days, the former X Factor judge is happier, healthier, and more outgoing—onstage, at least.

"I get past my shyness by making everything about others and not thinking about myself," the "Don't Hold Your Breath" singer said. "That's what I did on The X Factor—I can be goofy and playful when it's about the acts. They are like my babies. But when I'm off stage, I'm not as big and animated." 

She also makes time for her longtime boyfriend, Formula One racer Lewis Hamilton

"It’s something crazy romantic," the brunette says of her six-year long romance, adding, "Relationships are hard and having to hold a long-distance relationship is even harder."

Scherzinger, who has been on-and-off with the 29-year-old since 2008, went on to say, "It’s kudos to us for growing and trying—there’s so much love there. It’s just the distance, it’s not natural for anyone. But I’m good and I’m happy.”

The August 2014 issue of British Cosmopolitan hits newsstands on July 3.