A Song for One Friendship, a Video Starring Another: IU's 'Dear my crazy soulmate'
The introductory note IU attached to “Dear my crazy soulmate” is a single line: “To Yoo In-na.” No comeback essay, no concept statement — just the name of the actress she has been close with since they met on the 2010 SBS variety show Heroes. The song, whose lyrics IU wrote herself, is addressed to a best friend you plan to grow old with.
Then the video starts, and IU is not the lead.
The leads are Na Moon-hee and Kim Young-ok
The main characters of this video are veteran actresses Na Moon-hee and Kim Young-ok, playing two women whose friendship has crossed most of a lifetime. IU appears as a neighborhood police officer, paired with actress Shim Dal-gi — and the two of them function as the story’s helpers, not its subject.
The plot turns on an absurd workaround. Na Moon-hee’s character is a prison officer, and a changed shift ruins the pair’s plan to celebrate her birthday. Kim Young-ok’s character breaks the police-box window so she will be arrested and taken to where her friend works. The two younger officers catch on, and when she returns to repeat the plan, they applaud and cheer her on. The law, in this video, takes one look at a friendship like that and decides its job is to help.
It is a comedy in shape, but the reason it lands is the premise underneath: these two would still come get each other, at any age, at any cost. That is the song’s promise acted out.
The casting is the subtext
Here is the detail that turns a sweet video into a pointed one. Kim Young-ok and Na Moon-hee are not just two famous actresses of the same generation — they joined MBC’s inaugural voice-actor class together in 1961. They have been colleagues ever since — sixty-five years. Talking about the shoot on her YouTube channel, Kim Young-ok said she was glad IU “chose us grandmothers,” and that the video would be a chance to show her chemistry with Na Moon-hee — adding that the older she gets, the more she realizes how precious a friend you can open up to really is.
So the layers stack like this: IU writes a song to a friend of more than fifteen years, then hands the screen to two women who have worked side by side for sixty-five. The video doesn’t need to argue that some friendships last a lifetime. It hired the proof.
The other half: “Unknown Planet”
“Dear my crazy soulmate” is one of two title tracks on the digital single 이 별로부터 (Unknown Planet), which brought forward two songs from IU’s delayed sixth studio album — her first new music since the 2025 single “Bye, Summer”. (If the phrase “double title track” is new to you, here’s how that works.)
The other title track’s name is a piece of wordplay that doesn’t survive translation. Written with a space, 이 별로부터 reads “from this star” — matching the official English title “Unknown Planet.” Written without one, 이별로부터 reads “from farewell.” Same letters, two songs’ worth of meaning, and the official English pick quietly tells you which reading leads.
Both songs came out September 10 at 6PM KST, but only one video came with them. The “Dear my crazy soulmate” video went up alongside the songs; the full “Unknown Planet” video waited for the slot the official teaser had named: midnight at the start of September 16. It went live about a minute early, which is why YouTube stamps it the night of the 15th. One single, two songs, two videos five days apart — a release built the same way the first video frames friendship: in pairs.