Recently, K-netizens and fans have been shocked by the appearance of Seventeen's sasaeng fan on the preview of the popular variety show 'The Return of Superman.'

Sasaeng fans, also known as obsessive fans, are a phenomenon in the K-Pop industry that has become a growing concern in recent years. These fans are known for their extreme and often dangerous behavior, including stalking, invading the privacy of their idols, and even causing physical and psychological harm to their idols or other fans.

The appearance of this particular Sasaeng fan in 'The Return of Superman' teaser has raised alarm bells among fans because this particular Sasaeng fan had been known as Seventeen's Homma - fansite operators who take high-quality photos of their beloved idols.

The Sasaeng fan had previously posted photos of Seventeen's Joshua and Jun with two adorable children. The photos were posted on March 27, and fans speculated that the two Seventeen members were filming 'The Return of Superman' because there was no official information revealed until April.

Then on May 3, it was confirmed that Joshua and Jun are appearing on the show after 'The Return of Superman' uploaded teaser photos.

This was when fans spotted the Sasaeng hiding in the background of the official teaser photos.

Many fans and netizens are outraged since it is highly likely that the Sasaeng fan had stalked or gotten information on Seventeen's schedule through illicit ways.

Netizens commented, "As soon as I saw the photos, it gave me chills...Imagine you find photos that you weren't aware of. It's going to feel you're being watched 24/7," "That's actually really scary," "She's a really famous Homma. I didn't know she even went through that extent. That's just so chilling," "I think KBS released the photo on purpose," "I really wonder why they live like that," "I really wish they would sue them," "Does she get anything for watching them 24/7 like that?" and "This is actually disturbing."