You haven't phrased your question clearly. Do you mean How well do you know Kate Hudson? in which the answer would be 'Not at all' since of course I have not met her. OR, Do you mean How MUCH do you know about Kate Hudson?
In that case I would answer that i have some bare facts such as her mother being Goldie Hawn, her sons by different men and her recent baby girl by a third man with whom she hope to have a lasting loving relationship. Also, that Kate has had an athletics wear business in addition to her income from several films over the last decade, in which she starred.