'I had to listen to Dee's voice a lot in order to find my own,' Idina Menzel's sister Cara says of growing up alongside the Broadway star

Sisters in song!

Idina Menzel and her sister Cara Mentzel teamed up to sing “Never Never Land” to coincide with the upcoming release of Mentzel’s memoir, Voice Lessons: A Sisters Story.

The Broadway actress, 46, explains in the video that Peter Pan was the first musical she and her younger sibling saw together, and the experience “changed our lives.”

Credit: Idina Menzel/Instagram

Mentzel’s book (she kept the “T” in their last name, while Idina dropped it) tells of her instant bond at birth with the future Frozen star — before being separated in infancy due to a case of whooping cough. Following a year in the hospital, Mentzel reunited with her older sis and the family soon moved from New Jersey to Long Island to ease her father’s commute to New York City.

Though Mentzel’s young illness put the attention on her at first, Menzel soon stole the spotlight, forcing the younger child—now an elementary school teacher and mother of two—to navigate her own path.

“I had to listen to Dee’s voice a lot in order to find my own,” Mentzel, 43, says. “It feels like a really appropriate metaphor.”

RELATED VIDEO: Idina Menzel Is a Princess Bride in Her Wedding Dress — See the Photos!

Menzel agrees that while she went on to pursue music professionally, it’s always played a role in both of their lives. “It’s sort of come full circle that we were these two little girls, me trying to give her voice lessons,” says the Tony winner, who married her Rent costar Aaron Lohr last month. “Forty years later, we’re in a recording studio and I’m doing the same thing.”

Voice Lessons: A Sisters Story, which includes a foreword by Menzel, is available in bookstores and digitally Oct. 10.