Danielle's sons George, Harry and Archie
The model took to Instagram on Thursday to upload two deeply personal photographs of Harry as a newborn in hospital back in 2011, telling fans about her son's struggle to survive.
Danielle wrote: "Today is world prematurity day! This picture is my Harry born 10 weeks early and thanks to the fast thinking of the nurses and Drs at Good hope hospital and@heartofenglandcharity my baby survived by placing him into a plastic bag to keep in the heat... I'll never forget this day thanks to all that helped."
She added: "Just one more picture of my baby Harry so tiny but such a little fighter!! I started a just giving page when he was born and all the money is going to The heartlands neonatal unit #HEFT."
Danielle added a link to Harry's JustGiving page here.
Danielle gave birth to son Harry in July 2011. He weighed just 4lbs 4oz and at the time she tweeted: "Thanks for your kind messages. Feeling very emotional. Please pray for our little boy, hope he can be home with us soon."
Harry, now five, is Danielle's second child with now ex-husband, footballer Jamie O'Hara. They're also parents to sons Archie, six, and George, two.
Marking Harry's fifth birthday this summer, Danielle had said: "Can't believe my little miracle Harry is 5 today, nearly never made it so many times but he has gone from strength to strength love you so much my angel."