On March 11, NU'EST shared a listening preview of the upcoming tracks from their Best Album, 'Needle & Bubble'. 

The listening preview clip also teased some unreleased jacket photos from the Best Album, and fans were quick to notice something unique about the jacket images which were used as "album artworks" in the clip. 

Fans realized that each of the jacket cuts revealed in the listening preview clip recreated NU'EST's past jacket photos from their 10-year career.

Netizens commented emotionally,

"We will not forget you NU'EST! We will wait for your return!!"

"This is making me cry TT."

"OMG it's really the end..."

"You can really tell that this the final album. It's so sad but so beautiful."

"I'll cheer on the NU'EST members where ever they are TT."

"In the past they said in an interview that they wanted to be a group for a long time together TT. Was this really the only option..."

"This is the first time I've seen an idol group say farewell properly like this."

"I can't believe this is happening TT."

"I love you NU'EST, my last idol group..."

Meanwhile, NU'EST's final best album 'Needle & Bubble' will be out on March 15 at 6 PM KST, and will mark the conclusion of NU'EST's promotions as a group.