Chara

Mari Marui  (丸井マリ Marui Mari) is a character introduced in the episode I'm Mari-chan.

Story
Mari is an idol whom Doraemon is a big fan of. After Mari disappeared from a shooting, Doraemon surprised to see her sleeping on one of the pipes in the Open Lot. She was invited on Nobita's house and stated that she want to escape from her work. Doraemon used the gadget Substitution Bar to swap the places of Nobita and Mari.

Mari as Nobita enjoys being with Gian and Suneo while Nobita as Mari is stressful answering the interviews and ends up messing it.

Doraemon
He idolizes Mari. He help Mari escape from Media by swapping bodies with Nobita.

Nobita
He invites Mari to his house. He also agrees in swapping bodies with her.

Gian and Suneo
While in Nobita's body, she enjoys being with them.