Mariah Carey: Whitney Houston's 'When You Believe' partner 'heartbroken'

As quickly became evident following the news of singer Whitney Houston's sudden death on Saturday (Feb. 11), friends and colleagues from the musical community are stunned.

This included fellow pop diva Mariah Carey, who shared her feelings with fans via Twitter, "Heartbroken and in tears over the shocking death of my friend, the incomparable Ms. Whitney Houston.

"She will never be forgotten as one of the greatest voices to ever grace the earth."

Carey also changed her Twitter avatar to a 1999 picture of her and Houston embracing.

Positioned as rivals, the two singers teamed up in 1998 to record the song "When You Believe" for the animated film "The Prince of Egypt" soundtrack.