Naomi admitted to heat magazine: ''Kate introduced me to him at the Olympics. And I said to her, 'Whose son is he? Is he one of our model friends' kids that I just missed out on?' I didn't know who he was.
''Kate was like, 'Stop! No! You must know him.' ''
Despite her own global success, Naomi admits she gets star-struck, but tries to avoid it by keeping her distance from people she admires.
She said: ''Of course I get star-struck, but I don't run up to the person, I just look from afar.
''I saw Michael Douglas' dad Kirk in [restaurant] Cipriani in New York once. He said, 'Come here young lady!' I was like, 'Oh my God!' ''.
And while Naomi had no idea who Harry was, she is a big fan of 'The X Factor' - where One Direction first found fame - and its creator Simon Cowell.
She said: ''I'm a big fan of Simon Cowell. Everything he touches turns to gold and he gives people who have hopes a chance to really make their dream come true.
''I can only watch 'The X Factor' if I'm in the country. I know I can watch it on YouTube, but it's always a few days later and by that time someone's told you what's happened.''
He also slapped a jet-lagged Taylor Hawkins.
The acclaimed performer had just cancelled touring due to a battle with cancer.