User blog comment:Jimeee/Skyrim 1.9 beta update adds Legendary difficulty and raises level cap (Updated Apr 8th)/@comment-64.135.210.118-20130314140407/@comment-66.183.40.2-20130315012006

You get all of the perk right away, so if you heave ten perks into a skill, then legendary it, you should get them all back to place in other skills immedietaly