The One Direction singer recently purchased a £3 million property in London's exclusive Primrose Hill and has asked the supermodel for her advice on the interior design.
A source told The Sun newspaper: ''Harry has a rough idea of what he wanted the place to look like but didn't really know where to start.
''Kate has given him a list of her trusted furnishing contacts and her favourite shops and told him to get on to them. She's even given him the number of her florist.
''Kate thinks Harry's really sweet and she's more than happy to help him out.''
Earlier this month, it was revealed Harry had ordered pictures of Rihanna and Kate Moss for his new home.
The 18-year-old hunk splurged £100,000 on works by urban artists Banksy and Bambi depicting the famous beauties.
Art trader Lenny Villa said: ''We've had a call from a dealer who says Harry is looking for investment art, but modern and funky.
''We're sending him Bambi's painting of Rihanna and a Banksy print of Kate Moss. Harry knows Robbie Williams and Brad Pitt both own a Bambi.''