Zac Efron in a Bombas video.

ZAC EFRON ACTS UP: Zac Efron’s latest big-screen role is in “The Greatest Showman,” but he also has a smaller one in Bombas’ latest video.

Rather than sing, dance or act, he barely speaks and winks in one cameo and slurps a bowl of cereal in another with the company’s cofounders David Heath and Randy Goldberg doing the same. All three wear matching pajamas and different versions of Bombas socks. Lighthearted as his role is, Efron’s support is part of a three-and-a-half-minute flick that plays up the brand’s charitable ethos. Taking a page from Toms Shoes’ giving strategy of one pair purchased leads to one pair donated, Bombas has donated more than five millions pairs of socks to the needy since the company was started four years ago. After reading on Facebook that socks are the most requested clothing item in homeless shelters, Heath and Goldberg set out to try to do something about that.

Toms founder Blake Mycoskie is also featured in the video. This year, Bombas’ charitable efforts included providing 20,000 pairs of socks for hurricane relief efforts and 40,000 pairs to homeless veterans. Staffers at Bombas have donated their time to various causes, too, amassing 4,000 hours through volunteerism.

Efron has been a fan of the brand for a while and supportive of its product and mission, according to a company spokeswoman. This fall, he also stepped in front of a video camera for Columbia Sportswear, wear-testing its performance pieces in all sorts of rugged settings, including climbing to the top of the Continental Divide with his brother Dylan.

Bombas’ own road map will continue to focus on the impact of its mission, as well as product innovation. In 2018, the plan is to expand the sock assortment with new styles, materials and technologies, while the team also explores product expansion into other categories, which a spokeswoman declined to specify.