Peter, whose 23-year-old girlfriend Emily Macdonagh gave birth to their first child Amelia in January, also has 8-year-old Junior and 6-year-old Princess with ex-wife Katie Price.
However before the 41-year-old became a biological father, he took on the role of father to Katie Price’s eldest son Harvey, now 11.
Speaking about his experience as a stepfather, the popstar admitted:
"I always say it was Harvey who taught me to be a father before I became a biological dad.
"He changed me from a boy into a man. It is something I will never forget."
Speaking about the latest addition to his family, Pete revealed:
"Amelia is very placid, very sweet.
"Sometimes when we put her down to sleep she will have her eyes open for an hour or more and not make a sound. She is just so content."
Meanwhile Katie Price shared a picture of her bottle-feeding fourth child, baby Jett with husband Kieran Hayler, by her stables.
The new additions have proven to be a great excitement to older siblings Junior and Princess, with Princess being particularly thrilled about finally having a little sister.