Nagisa and Honoka starred in the first TV series Futari wa PreCure (2004-2005) , then Hikari joined its sequel Futari wa PreCure Max Heart (2005-2006).
Twin sister manga artist Futago Kamikita announced on their official Twitter that the three main PreCure girls from the the first two TV series, Nagisa Misumi/Cure Black, Honoka Yukishiro/Cure White, and Hikari Kujo/Shiny Luminous make a guest appearance in the latest ninth chapter of their manga adaptation of the ongoing 15th TV series Hugtto! PreCure.
They say they rewathced the 39th episode of Futari wa PreCure Max Heart for reference.