SEOUL – A retro viral challenge is trending again, thanks to South Korean stars such as IU and Park Bo-gum.

The Ice Bucket Challenge, which swept social media in 2014, saw celebrities and netizens taking part to douse themselves with buckets of ice water to promote awareness of a neurodegenerative disease called amyotrophic lateral sclerosis (ALS). It is more commonly known as Lou Gehrig’s.

They were usually given 24 hours to respond after being tagged in the challenge or make a donation to a charity.

On Monday, singer Sean, one half of the pioneering hip-hop duo Jinusean from the late 1990s, kicked off the challenge with a heartfelt message about his work with Seung-il Hope Foundation over the past decade.

The foundation was set up in the name of former basketball coach Park Seung-il, who was diagnosed with ALS in 2002 when he was 31. It is building the first ALS hospital in South Korea.

After Sean, 50, poured a bucket of water over his head, he nominated singer-actress IU, 30, former footballer Cho Won-hee, 40, and actor Park Bo-gum, 30.

They all gamely took on the challenge and nominated three more people each. The challenge has since snowballed to at least 10 K-idols taking part within three days.

These include actor Kwak Dong-yeon, 26, actress Lee Joo-young, 31, singer-actress Nara, 32, girl group member Mimi, 28, from Oh My Girl, and boy band member Q, 24, from The Boyz.

As these stars – who have millions of followers on Instagram – have tagged their celebrity pals in their videos and given them 24 hours to respond, the challenge looks set to go viral again in South Korea.