British actor Felton has described Helena, 45, who plays Bellatrix Lestrange in the wizard franchise, as 'beautiful'.
The 23-year-old told British Metro newspaper: 'I had a little boy crush on Helena Bonham Carter - she's very beautiful.'
Tom admitted that the Oscar-nominated actress once gave him tips about how to cry on camera.
He said: 'Helena gave me advice about crying in a scene. She said tell your brain you're not allowed to cry and then it's more likely to happen.'
Asked if he was surprised that 21-year-old Emma Watson recently confessed that she was once attracted to him, the star added: 'No, because she'd said it before a few years ago on TV. We've been friends for a long time and it's very flattering.'
Harry Potter and the Deathly Hallows: Part II opens in cinemas today.