"It's not only Halloween. It's about once a week," Johnson tells ET's Kevin Frazier. "I'll put on the Pikachu costume. It's a whole thing."
Johnson says that the idea for the costume came when he and his family were visiting a pumpkin patch in Hawaii.
"There was a guy in a Pikachu costume and [Jasmine] went crazy," Johnson says. "I'd never seen her react that way before."
While he's thrilled to put on a show for his baby girl, Johnson admits there's one drawback.
"I'm sweating my a** off in that thing," he explains.
Johnson is clearly a rock star at home, but he's about to be a hero to many more children with the release of his upcoming Disney animated movie, Moana.
The story is set 3,000 years ago in Oceania and follows young heroine Moana, who sets out on a daring voyage to save her people by reclaiming an ancient gem. Along the way, she encounters shapeshifting demigod, Maui (Johnson).
As is the case with many Disney flicks, music is a major element in the movie, and Johnson said he enjoyed singing.
"It was awesome. It was unlike anything I've ever done before," Johnson shares. "I grew up singing. We come from a singing family, but never in a studio."
Johnson also praised Tony-winning Hamilton creator Lin-Manuel Miranda, who joined the movie's musical team and wrote the song "You're Welcome."
"He did a lot of research and he goes, 'I know what comfortable range you sing in, but I'm also going to challenge you and your voice too as well,'" Johnson recalls. "It was a lot of pressure but it was awesome, because I love making movies."
The story is close to Johnson's heart, given his strong ties to the South Pacific. Half-Samoan, the 44-year-old actor was bestowed the chiefly title of Seiuli during a visit to the Polynesian island in 2004, and spent some of his high school years living in New Zealand.
As a father to two daughters, Jasmine and 15-year-old Simone, the movie also strikes a personal chord as he was able to see similarities between his girls and Moana.
"It's very special," he says.