Whitney Houston's ravaged voice
Whitney Houston's voice was almost destroyed by drugs.
Following years of heavy smoking and drug abuse, Whitney's singing was reportedly "unrecognisable" when she began recording her new album.
A source told Britain's Daily Mirror newspaper: "She was smoking a lot and taking a lot of drugs. Her voice was almost unrecognisable."
Whitney - once dubbed 'The Voice' for her five octave range - was sent for singing lessons by industry executive Clive Davis and is now back to her high-note best.
The source added: "Thousands have been shelled out to train her back up to the original. But now she sounds terrific - she is going to blow everybody away."
Whitney's new, as yet untitled comeback album, is set for a November release.
In 2006, Tina Brown - the sister of Whitney's now ex-husband Bobby Brown - claimed Whitney was living in squalor, and hopelessly addicted to crack cocaine.
She released photographs to a US magazine showing the star's bathroom littered with drug paraphernalia, including a crack pipe.