The 40-year-old supermodel has never met her dad - who is not named on her birth certificate - and has no interest in tracking him down out of respect for her mother Valerie, who was left to raise Naomi alone when she was just 18.
She said: "I`ve thought about it. But I don`t want to hurt my mum. She`s been through a lot. She went through cancer. She has faced a lot of challenges. She travelled the world and she dealt with any situation.
"Is he alive? I don`t know."
Naomi insists her childhood was a happy one, despite her absent father, and she knew she wanted to be a performer from the age of just three.
However, she admits her main motivation to get into the prestigious Italia Conti stage school was the promise of a new doll from her mother - who was a former ballet dancer.
She recalled: "I had to audition to get into the school. Auditions for 500 children! My mum said, `Naomi, there`s no way you`re going to get it. But if you get it, I`ll take you to get a Sindy set at Hamley`s (London toy store). And I wanted that Sindy set!"