Viral superstars LOONA dropped a surprise teaser at midnight on December 10, teasing fans about the type of release that the members have in store for their comeback.

According to a report by All Kpop, LOONA's agency, Blockberry Creative, released the unannounced teaser which bore the numbers "365" and not much information. The numbers appeared layered on top of each other atop a black background, along with the caption "Through the heart of the 365-day moon."

It is expected that 365 will be the title track for LOONA's comeback on December 13 at 6 pm. The label also confirmed that the girls would hold a Premier Greeting event at Seoul's YES24 Live Hall on December 14.

LOONA had an eventful year as they staged their first comeback in February with the much-celebrated X X album and the carrier track Butterfly. The song received a lot of love from fans all over the world for its message of celebrating one's voice. According to the group, they wanted the fans to feel like they were part of LOONA when they made the song.

LOONA was also among the artists who performed at the 2019 KCON in Los Angeles, California, in October. During their US stint, the members talked about their global success on social media. They also talked about becoming LGBT+ icons in the digital space.

According to the members, they were surprised about their viral success, but they were thankful for the fans' support, which gave them the motivation to do even better.

During the interview, YOONA's Yves said that they were also happy that their song, Heart Attack was being celebrated as a positive slant to LGBTQ+ representation.

"We heard about such reactions and interest, and we're so very thankful. When the music video first came out, it was about yearning. We were so entertained that it could be interpreted in such a way. We're so thankful for the interest," she said in a Billboard interview.

"We appreciate how people find it appealing, and we feel motivated to work harder," she added.

In the same vein, they thanked the fans for their appreciation of Butterfly's message of empowerment for women because it was LOONA's goal to inspire women to reach their full potential to change the world. Members of the Kpop group further said that they were glad that fans were connecting with their songs.