When Peter Andre married Katie Price in 2005 he vowed to be the dad that Harvey didn't have.
While the marriage only lasted four years, Peter has continued to share messages of support for Harvey including this week when he wished the teenager a happy 18th birthday.
However, there has been a time when Peter slipped out of his life, with Katie bemoaning that all the male role models in Harvey's life turning their backs on him.
After Peter met Katie in the Australian jungle when they appeared on I'm A Celebrity together in 2004, there was a whirlwind romance which led them up the aisle less than a year later.
There seemed to be an unbreakable bond between Peter and his stepson and there was even talk that Peter would adopt Harvey, as his real father, footballer Dwight Yorke, had not accepted him from the beginning.
Harvey was found to be blind, with septo-optic dysplasia, which makes optic nerve development unpredictable.
He has also been diagnosed as being on the autistic spectrum and to have Prader–Willi syndrome.
After having two children with Katie, Junior and Princess, Peter split from the reality star but was gushing in praise for Harvey.
Writing in his New! magazine column at the time, Peter revealed: "There have been a few times recently where he's been to my house and I've been to his.
"Harvey will always be special to me and I just want him to be happy. He's a great kid!"
The reason why he will always have something for Harvey came out during an interview with KIIS FM, as Peter admitted: "The first child that taught me how to be a dad was Harvey."
Throughout the years since splitting from Katie, Peter has shared not-so-cryptic messages on Harvey's birthday, without mentioning him directly.
On Harvey's 15th birthday, Peter posted on Twitter : "Happy birthday to a very special boy. Hope you like your prezzies."
While Katie bemoaned on social media that Peter gradually saw less and less of Harvey, and that she was all he had now.
Katie said: "We have gone on a journey, me and Harvey, and all I know is that no one will ever take him away from me.
"When you divorce you have to share the kids. But with Harvey there's no one.
"Well, look, Dwight don't want to know. Someone else doesn't see him anymore. He's just got me, you know?"
This was backed up by Peter gushing about becoming a dad again with wife Emily, telling OK! Magazine at the time: "I just couldn't wait to tell everyone [we're expecting a baby]. I was buzzing, I still am.
"This is my fourth child, so it's incredible!"
He continued: "I was only saying a few weeks ago that I'd like two more, because Amelia is the dream child and Princess and Junior are so sweet."
Fans of Katie saw this as a sleight on Harvey as Peter didn't seem to count him as one of his children and excluded him from the family unit.
This may be due to the logistics of seeing Harvey and Peter had always stuck by his statement in 2009, when he told the Daily Mail how he thinks Dwight Yorke must feel.
Peter said: "I have been a real father of Harvey and he calls me Daddy. I guess that sticks in Dwight's throat."
The special message as Harvey enters adulthood is a reminder that Peter is still a father figure in his life.
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