When director Yi Xiaoxing went to a public bathhouse with his friends, he had a novel experience of the "scrub-dirt" service, a prevailing type of service in northern China, for the first time.

Typically, in "scrub-dirt" service a worker wraps a towel on one hand, and scrubs the customer's body before giving a massage. For most locals in northern China, it is complete relaxation.

Rejuvenated by the experience, Yi did more research and discovered this service could date back to hundreds of years ago, which inspired him to write the script of his latest comedy, Bath Buddy.

The film, which Yi is also directing, opened in theaters across the Chinese mainland on Dec 11. With the hit franchise Surprise which includes a feature-length film, several online series and a book, Yi has been ranked as one of the most popular self-made comedy creators rising to fame from the internet.

Starring actors Peng Yuchang and Qiao Shan, the film begins with a tycoon having a wingsuit diving accident, which causes him to temporarily lose his memory and get stuck in a small town.

A shabby bathhouse worker, once bullied by the tycoon, bumps into him and pretends he's the worker's younger brother. Their conflict has develops into a real brotherhood-like bond after experiencing a series of misfortunes during an international bath skills competition.

Aside from the lead actors, the film also features actresses Bu Guanjin and Wei Qing, as well as actors Jin Shijia and Huang Kaixiang.

Actor Peng, credited for the 2018 hit comedy Take My Brother Away and the 2020 sports film Leap, said he spent a month to learn bathhouse service skills with a veteran.

The film has just opened, topping the country's single-day box-office charts by raking 14 million yuan ($2.14 million).