The 47-year-old singer was devastated to learn that the 38-year-old former Girls Aloud star had been diagnosed with breast cancer earlier this year, but has commended Sarah for going public with her health battle as she will be able raise awareness for others suffering with cancer and encourage women to check themselves for lumps.
Writing in his New! magazine column, he said: ''I was so sad to hear that Sarah Harding has been diagnosed with breast cancer. I want to praise her for speaking out about her illness and I really admire her for being so open and brave. I really think it will raise awareness for others who are going through something similar.
''I just want to say that my whole family is thinking about her and we're praying she'll be OK and that she stays strong.''
Peter has had firsthand experience of cancer as his older brother Andrew died from kidney cancer in 2012 at the age of 54. Since then, the 'Mysterious Girl' singer has been an ambassador for Cancer Research UK.
Sarah revealed her condition last week by taking to Twitter to tell her fans that she is fighting cancer.
She wrote: ''Earlier this year I was diagnosed with breast cancer and a couple of weeks ago I received the devastating news that the cancer has advanced to other parts of my body.
''I'm currently undergoing weekly chemotherapy sessions and I am fighting as hard as I possibly can.
I understand this might be shocking to read on social media and that really isn't my intention.
''But last week it was mentioned online that I had been seen in hospital, so I feel now is the time to let people know what's going on and this is the best way I can think of to do so. (sic)''
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