YOU DAYEON (Korean: 유다연; Chinese: 柳多戀; Japanese: ユ・ダヨン), formerly known as Seoryn (서린), is a South Korean soloist under MMG. She is a former member of the girl group LIPBUBBLE and made her solo debut on October 20, 2023 with the single album "down down down". She is also known for participating in Mnet's reality survival show Girls Planet 999.

You Dayeon was first introduced as a member of LIPBUBBLE under the stage name Seoryn on December 22, 2016. She officially debuted in the group on March 22, 2017, with the group's first digital single "Popcorn". She left the group in Spring of 2019 and later joined the dance studio 1MILLION.

On July 7, 2021, she was confirmed as a contestant on Mnet's newest reality show Girls Planet 999, along with the other participating trainees, through the prologue trailer. In the fifth episode, which was aired on September 3, it was revealed that Dayeon, along with her cellmates, was unfortunately eliminated.

On October 15, 2023, she announced that she will make her solo debut with the digital single (labeled as a single album) "down down down". Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.