During the online press conference for the release of '1+1=1' that was held on September 9, HyunA explained that the song "Deep Dive" was written when she was away from Dawn. She explained, "I received this song from Dawn when I was away at LA because of a beauty pictorial."
HyunA reminisced back at the time when she first heard the song and explained, "I was doing my morning exercise. I had my hair tied up and I was running. There were many trees and cacti around me. I still get goosebumps when I think about that time. When I heard the song back then, I thought 'I really want this song to be released,' but I never thought I would be the one to sing it."
She also explained, "I think that this album has the concept of fairytales. This song gives the feeling of diving into fairytales. We decided to put this song as the first track to the album because we thought it's the song that best expresses the color of this album."
Dawn went on to further explain the musical aspects of the song and said, "This song is based on short string sounds, repeated synth sound, with the 808-base as the foundation. This is a song that has a mix of hip hop and R&B genres." Dawn further went on to explain how he felt as he wrote this song. He explained, "I think my heart was fondly longing at that time. When I made the song and listened to the song, I felt the warmth coming from the song itself. It feels like a fairytale."
After hearing Dawn's explanation about the song, HyunA asked Dawn, "You must have missed me since we were apart for a long time." In response, Dawn said, "That's right. It was because we were apart for like a week," as he expressed his affection towards HyunA.
Dawn then concluded by saying, "I think couples who are in love can really empathize with this song" and recommended this song to lovers.
Meanwhile, HyunA and Dawn worked on the title track "PING PONG" together and released their duet album '1+1=1' on September 9.