On April 21, 2020, SM Entertainment revealed that Irene and Seulgi would form Red Velvet's first sub-unit.

[2] Before their debut as members of Red Velvet, the duo, as part of SR14G (SM Rookies 2014 Girls), notably performed a cover of "Be Natural", a song that was sung originally by S.E.S.

[3] Their cover was well received by the public and Lee Soo-man, which eventually prompted the creation of their subunit.

[8] From July 8 to September 8, the duo also starred in their own reality show, a spin-off of their group's Level Up Project!.

[9] On August 18, 2020, Irene & Seulgi appeared and performed at Time 100 Talks, a live event series wherein global leaders talk about innovative solutions to urgent global problems, and encourage cross-disciplinary action among stakeholders.