The famous dad revealed the four-year-old has never had a haircut and he's the reason why.
Speaking to Yahoo, he said: "About a year ago, my wife said, 'Maybe we should cut Harper’s hair.'
"I was like, 'No! We need to grow it. Do. Not. Touch'.
"Since she was born, we haven’t cut it. That’s why it’s pretty much down to her knees."
When the interviewer suggested Beckham had saved his daughter's hair, he replied: "I had to. It's just so good, isn't it?".
Beckham frequently shows just how long his daughter's hair is on Instagram.
Although Beckham wont let any scissors near his daughter's hair, he admits he is happy to play hairdresser to his sons - Brooklyn, 16, Romeo, 12, and Cruz, 10.
He added: "I do cut my sons’ hair from time to time. When they have a buzz cut, I do it."