The 'Candy' hitmaker, who has done two stints in rehab himself, is concerned for the well being of the 20-year-old singer and is worried the staggering level of fame she has achieved could have a negative effect on her, reported Daily Mirror.
"Miley's got the world talking and looking at her. And the spotlight that's now upon her is rehab-making. It has a detrimental effect on your psyche. I've had a similar light shine on my direction and it finished you up - for a long time," Williams said.
"She's just a kid. She's a kid who looks as though she's rebelling against her father and rebelling against the industry that put her in a Hannah Montana-shaped box," he added.