On April 21st, it was reported that SEULGI and IRENE from SM Entertainment group Red Velvet will have a duet together. It is the first sub-unit from the girl group.

On June 21st of 2020, the duo “SEULRENE” revealed their first comeback teaser for “Two Shadows.” It was uploaded on Red Velvet YouTube Channel. Their first mini-album is named “Monster.” and will be out on the 7th of July.
The title track will be named “Two Shadows.“
The video teaser for “Two Shadows” is in black and white, representing a dark and gloomy atmosphere. A mysterious creature appears which could be a wolf as its eyes and fur can be seen.
The video is also captioned with “One individual. Two shadows.” It could probably be IRENE and SEULGI representing the creature’s two personalities. Red Velvet is known to have both cute and dark concepts so maybe it could fit the concept of the diverse personas of the presumed wolf.