The 37-year-old supermodel bought the wine-making facility as a gift for The Kills rocker, after turning to her former boyfriend Johnny Depp - who owns an estate in the Massif des Maures hills near St Tropez - for advice on what to look for.
A source said: "One of the first people Kate consulted about buying the vineyard was her ex-boyfriend Johnny Depp, who also owns an estate in France.
"Johnny was incredibly encouraging and told Kate that producing wine has been an amazingly rewarding hobby."
The catwalk beauty was inspired to buy the grape-growing fields after visiting the South of France and trying out the region's various wines, and she now plans to name one of the bottles after herself.
The insider added to the Daily Mirror newspaper: "Jamie and Kate have been holidaying in the South of France since their wedding and have been touring through Provence looking for suitable estates.
"Naturally, this process has included a considerable amount of wine-tasting along the way. Jamie really appreciates a good drop and is quite knowledgeable about vintages and grapes, and Kate even picked up a couple of handy tips.
"Kate is planning on naming the wine after herself and has even suggesting using a Merlot grape to produce the inaugural Vin de Mossot."
In addition to wine, Kate also wants to make her own soap and has been creating bars with flowers from her garden at her home in the Cotswolds, Central England.
A source said: "Kate loves her new hobby, she's gone soap mad. She's been trying to master the art after one of mates sent her a batch of home-made bars, which she loved.
"She's adamant all the ingredients should be fresh and natural. She's sent quite a few to her girlfriends to try out. Depending on the feedback, she's thinking of releasing a range."