The end is nigh!!

My first potato plant with its purple leaves are starting to flower. Soon, I will be dining on purple potatoes from a purple plant. I assume it is the anthocyanins rather than a lack of phosphorous or high acidity. Never have grown purple ones before so I guess I will find out. I have acidified my soil and fertilized it with lots of phosphorus so neither should be an issue. I would love to know if this is normal for someone who has grown them in the past.