Katherine Jenkins has been left ''heartbroken'' by the death of her best friend.

The 33-year-old singer is mourning the loss of Polly Noble after she lost a seven-year battle against cervical cancer.

She posted a picture on twitter yesterday (12.05.14) of herself and her friend and wrote: ''Heartbroken. Rest in Peace my darling friend.''

And in another photo on her Instagram page, she added: ''Heartbroken - Sleep now with the angels.''

The pair became friends when they were both struggling singers in 2001, and Katherine was on tour when her pal called in 2005 to break the news she had cancer.

The classical star previously recalled: ''She didn't look or sound ill - it was just unbelievable.

''And of course the word cancer frightens the life out of me because I had watched my father die of lung cancer when I was 15.

''But he had been nearly 70, and Polly was just 24. She was too young; she had too much to live for.''

Polly underwent surgery, chemotherapy and radiotherapy and was eventually given the all clear for three years, but in 2010, she found a lump in her neck that turned out to be a secondary tumour.

Katherine previously said: ''This time her oncologist told her that although she could have more treatment, the cancer was ultimately incurable.

''She called me from the hospital with the news. Neither of us cried. We were too stunned.''