He's best known for wearing face paint, leather and gems as the frontman for Kiss. But Paul Stanley spent a big chunk of 1999 wearing a different costume – and singing a very different kind of music.

Inspired by seeing the show in London a decade earlier, Stanley took on the lead role in the Broadway musical The Phantom of the Opera for what would up being two extended engagements at Toronto's Pantages Theatre, beginning on May 25, 1999, and ending, appropriately enough, on Halloween of that same year. "Things went so well that the theater bought out the contract of the actor poised to replace me and had me take the show to the finish line," he explains in his book Face the Music: A Life Exposed.

Stanley describes the job as "a dream come true" and "an incredibly rewarding experience." As it turns out, Phantom also helped him come to terms with a birth defect he had kept hidden from the public for decades, and inspired him to join forces with a charity dedicated to helping children born with similar conditions.

At first, the Phantom gig was simply another mountain for Stanley to conquer. "I never want to be stuck in someone else's idea of what I'm supposed to do, or can do," Stanley explained to Much Music around the time of his first run. "For me, the challenge is always to find something exciting. If you're scared, it means that you're doing something good, you're pushing the envelope."

The first obstacle Stanley faced was learning how to use his voice in this new setting. He describes the rehearsals as "the hardest work I've ever done. Six hours a day. I went home every night slumped in the back of a taxi, exhausted emotionally and – because of the demands of singing a different way and the physicality of the role and the staging – physically." He worked with a vocal coach to figure out the breath control needed for the show's musical numbers. When he finally publicly performed as the Phantom, his efforts were rewarded with much praise – including that of bandmate Gene Simmons, who, after attending a show rushed backstage to ask his longtime partner, "Where did you learn to sing like that?"

Paul Stanley Talks About His Work With AboutFace

But soon Stanley realized why the show was affecting him on such a deep emotional level. "Every night when I occupied the character, I tapped into things buried deep inside of me. The mask. The hidden facial disfigurement. It haunted me." Unknown to most people at the time, Stanley was born with microtia, a condition in which the external ear is undeveloped.

Not only did this render him deaf in one ear, the ear was literally not there. This caused him to spend his childhood in constant fear of being exposed and mocked by his peers. In 1982 he endured a series of five reconstructive surgeries in which pieces of cartilage from his rib cage were used to create the framework of an ear, which was then grafted onto his head.

In Face the Music, Stanley describes how Phantom's climactic moment – when Christine rips off the mask hiding the Phantom's hideously scarred face – resonated with him personally: "I knew this scene. It was the scene I had feared my entire life: scrutinizing eyes staring at Stanley, the one-eared monster."

His performance impressed Anna Pileggi, from the charity AboutFace, enough that she reached out to Stanley, noting that he seemed to identify with the character in a way she hadn't seen in other actors. She went on to describe the work of her organization, which is dedicated to helping children born with facial differences. Stanley soon called her, told her of his mircotia and surgeries, and agreed to partner with AboutFace by talking to kids and their parents about his experiences.

"Children are our future, they're the innocents," he explained to Celebrity Soapbox, "and they are put in a position by a lot of people that is unkind and cruel. The best way to work around that is to educate people. I think it's easier to not stare at somebody if you know what their situation is." Stanley continues to work with AboutFace to this day, and promoted the charity's work during appearances on his recent book tour.

After The Phantom of the Opera, Stanley left the world of musical theater for a return to touring and recording with Kiss.

