Almost 10 years after their debut, I.O.I returns with an emotional track, Suddenly, from their reunion album I.O.I: LOOP. We break down the music video details, including Somi's viral kissing of Doyeon!

I.O.I is finally back after nine years, but it is their shocking teaser moment featuring Jeon Somi and Kim Doyeon that has taken over the internet. Here is everything about their comeback, concept, members, and why it is going viral.