Osbourne 'feels adrift without Rivers'

Kelly Osbourne apparently relied on Joan Rivers for "life guidance".

The two stars appeared on E!'s show Fashion Police together, but tragically 81-year-old Joan passed away earlier this month, following complications during a routine throat procedure.

Kelly, 29, formerly struggled with an addiction to painkillers and has had three stints in rehab. It's thought friends are worried her grief over losing her friend could push her over the edge again.

"She relied on Joan for life guidance, boyfriend advice and everything in between. Kelly has known Joan since she was a little girl and in past years has become her rock," a source opened up to British magazine new!

"Joan has never judged Kelly and has been her biggest supporter. Kelly has already said she feels adrift without Joan."

Kelly has been suffering with pneumonia recently and was even admitted to hospital. She's also been posting heartbreaking messages on Twitter, calling the day Joan passed "one of the worst days of my life".

Her first rehab stint was in 2004, with another following in 2005. The last was in 2009, when she spent 30 days at a facility.

Since then, she's made a promising presenting and fashion career for herself and shed weight to maintain a healthy figure. But now the future of Fashion Police could look bleak.

"She hates to admit it, but the show was a great motivation to stay on track," the insider added.

"She got her body back and her demanding filming schedule left her with little time to stray."