GUGUDAN member Kim Sejeong teared up because of the birthday surprise set up for her.

GUGUDAN shared a video on Instagram showing Kim Sejeong wearing a pink party hat and carrying a box with letters on top of it, as well as a bouquet of flowers. In the clip, the idol seems not to contain her happiness as she kept on crying. Also, T-ARA's Park Jiyeon can be seen in the video celebrating the special occasion with Sejeong.

The clip was uploaded with the hashtags "Happy Birthday" and "Sejeong." Aside from Jiyeon, the staff was also present at that moment to greet Sejeong. Fans who have seen the post also greeted the idol a happy birthday, and some even left sweet messages on the comment section.

Aside from her group activities, Kim Sejeong released several songs like "Flower Way," and original soundtracks of Korean dramas as well, such as "If Only" for the "The Legend of the Blue Sea," and "Lover" for "Mr. Sunshine."

Sejeong then started her acting career in July 2017, as the female lead of KBS2's teen drama titled "School 2017." She became more prominent because of this drama with her character, Ra Eun Ho, who attracted the audience with her cheerful personality. As a result of her passionate acting, Sejeong received the "Best New Actress" award at the "2017 KBS Drama Awards."

Kim Sejeong is currently starring in KBS's "I Wanna Hear Your Song," together with Yeon Woo Jin, Park Jiyeon, Kim Sang Kyun, Yoo Gun, and Lee Si Won. It is a romantic musical drama, where she takes the role of a timpanist named Hong Yi Young. Park Ji Yeon, on the other hand, plays as an arrogant violinist in the story.

"I Wanna Hear Your Song" is the second project of Kim Sejeong where she plays the female lead. It airs every Monday and Tuesday at 10 p.m. KST.