Play in this article ↓aespa Forever: The Surprise Winter Ballad Between Black Mamba and Next Level
- Category: Album & Song Guide
- Artist: aespa
KPOP NO1 Editorial · Sources checked October 22, 2026
Just two and a half months after a hard-hitting debut about a villain called Black Mamba, aespa released a gentle winter ballad. It wasn’t even a new song. Forever is a remake of a 21-year-old SMTOWN track, and its original writer arranged the new version himself.
A surprise announcement
On January 29, 2021, SM announced a surprise new single for February 5. Its full title is Forever (약속). The Korean word yaksok means “promise.” SM announcement
The original song is by Yoo Young-jin. It first appeared in 2000 on Winter Vacation In SMTOWN.com, a winter-season album, under the title Forever (아이의 크리스마스 선물을 준비하는 아빠들에게). That roughly translates as “to the dads getting their kids’ Christmas presents ready.” For aespa’s version, Yoo Young-jin did the new arrangement himself.
What the song sounds like
SM describes Forever as a medium-tempo ballad:
- warm acoustic guitar and strings
- lyrics with the pure feeling of promising forever to someone you love
- aespa’s fresh, clear voices at the front
SM also pointed out the contrast directly. Forever shows a different side of the group from the intense debut, Black Mamba. Later, SM described the release as aespa’s gift of music to warm fans’ hearts during the cold winter.
The snowball video
Forever came out on February 5, 2021 at 6 p.m. KST, with its music video released at the same time. SM says the video uses a snowball concept to carry the song’s warm winter feeling. SM release-day announcement
There was more to watch after release day. On February 6, 8 and 10, aespa posted The Performance Stage on their YouTube channel. These videos present the song with a different concept each time.
Our take: SM’s descriptions of Forever don’t mention the avatar story at all, unlike Black Mamba and Next Level. If the concept of the debut felt like a lot, this is an easy way in.
Two weeks, step by step
SM rolled the single out over about two weeks:
| Date | What happened |
|---|---|
| January 29 | Surprise announcement |
| February 3 | New teaser images: the four members in a dreamy, mysterious setting |
| February 4 | Music video teaser |
| February 5 | Single and music video released at 6 p.m. KST |
| February 6, 8, 10 | The Performance Stage videos on aespa’s YouTube channel |
SM: teaser images · SM: performance videos
Why a remake?
A remake has a history before the new recording. Forever had already existed as a Yoo Young-jin song for 21 years, and aespa’s version was rearranged by the same writer. So it isn’t a brand-new composition. It’s an older SM song given to SM’s newest group. aespa would do something similar three months later with Next Level, though that time the original came from a Hollywood soundtrack.
How it did
On Billboard’s World Digital Song Sales chart, Forever reached No. 11. So aespa were back on a Billboard chart, after Black Mamba. SM: Billboard result
Later in 2021, the UK magazine NME looked back at the group’s start. It noted that aespa had debuted with Black Mamba and Forever, before Next Level. So Forever counts as part of the group’s opening chapter, even though it’s a remake.
The release at a glance
| Format | Digital single, one track |
| Released | February 5, 2021, 6 p.m. KST |
| Original | Yoo Young-jin, from Winter Vacation In SMTOWN.com (2000) |
| Style (per SM) | Medium-tempo ballad, acoustic guitar and strings |
Format and date: aespa official discography
How to listen for the first time
- Play Black Mamba, then Forever, back to back. SM itself framed Forever as a different side of the group from the intense debut, so the contrast is the point.
- Listen for the guitar and strings. They’re what SM highlights about the arrangement.
- Remember why it exists. SM framed it as a winter gift to fans, released between two story songs.
Where to go next
- Go back to the debut: Black Mamba.
- Another remake, very different: Next Level reworks a movie soundtrack song and continues the avatar story.
- Meet the members: the aespa beginner guide.