Included free with first-print copies in Japan.
As previously announced, a product code to download Joker is included as a bonus with first-print copies of Catherine: Full Body in Japan for use in Babel and Colosseum modes. The Joker add-on will also be sold separately at a later date.
Catherine: Full Body is due out for PlayStation 4 and PS Vita on February 14, 2019 in Japan. A western release is also planned, but has yet to be dated.
Watch the footage below (from 1:27:25 to 1:33:00).