In an unboxing of the Dark&Wild album (English translation of unboxing here) by Suga, one of the members of BTS, he said:

Song produced by Suga (himself). Truth be told, this track has been made for quite some time already. I tweeted briefly about it before, wearing a hood and of my back, was it a black and white photo? Yeah, I uploaded something like that. The kids took that picture of me while I was working on it. (T/N: Could be referring to this tweet, but it’s not clear) And I think when that photo was taken, it was also the day that the recording for the track had ended. Anyway, it’s a song that I feel really proud of, and it’s a song that’s both pop and r&b.

In the case of the producing of the song, it all came out rather fast. Originally I was thinking about making a solo track, but the company and I decided that it wasn’t time yet for us to release solo tracks, so this album became one that everyone got to participate in. Yes, so it’s a track like that.

Personally for me in this album – it’s not that I had any selfish intentions – it’s not anything like that, but this track is my favourite.

In an [interview], Tony Jones (BTS' American Hustle Life Mentor) named it his second favourite track off their album, saying:

‘“Let Me Know” is also a really good record. I actually got to hear that before it came out at KCON backstage. My boy Suga pulled his phone out and said, “Hey I produced this track. Do you wanna listen?” So I heard it before but when I could hear it in speakers, that was a beast. Suga is amazing. He made that record. He produced the track, the hook, and everything.’