On October 27, f(x)'s Amber and Luna held a live streaming called "4 Walls LIVE with Amber&Luna" on Naver's V App.

The two members were able to express their excitement with f(x)'s comeback and reflected upon their debut days.

"We had a long break and did individual activities for a long time," Luna began. "We tried so hard this time just like our debut days."

Amber, on the other hand, agreed and added on to what Luna said.

"We worked as if we are back to the beginning. Our fans waited a year and three months for us so we prepared a lot," she said.

f(x) released their fourth album 4 Walls this week and made a comeback.

"We recorded for a long time for each and every song and really thought about what kind of songs to bring to our fans. I think we really became one as we minimized our individual activities and focused on our album," said Luna.

4 Walls is out now and f(x) are set to promote their album within the incoming days!