T wo years ago, RM of the wildly popular K-pop boyband BTS was serving as a soldier in the South Korean military when he received an offer from América Castillo, a museum curator in San Francisco: would he consider an exhibition of his private art collection?

“I loved it,” said RM (real name: Kim Namjoon) at the media preview of RM x SFMOMA: Between You and Me , a new exhibition that opened in San Francisco earlier this month and is co-curated by SFMOMA’s Castillo and Hyoeun Kim. “There aren’t many things that show a person more honestly than a collection they’ve built over a long period of time.”

The result is a multi-dimensional exhibition of 142 works of RM’s private collection of mostly Korean works, including paintings, calligraphy, sculpture and even a Pokémon animation cel, in conversation with 36 of the museum’s pieces.…