I.O.I's Sohye and Nayoung throw first pitch at Jamsil as '갑자기' hits #1 on Melon

Sohye and Nayoung took the mound at Jamsil Baseball Stadium on June 3 for the ceremonial first pitch and first bat ahead of a Doosan Bears vs. Hanwha Eagles game.

The whole thing started with a viral YouTube video. Someone had mixed Yang Ui-ji's cheering song—the 39-year-old Doosan catcher's anthem—with I.O.I's new title track 갑자기 and noticed they shared a similar melody. The meme took off online. Doosan announced the event on June 1.

"It is a great honor to stand on the mound at Jamsil Stadium," Sohye said. "I will throw with full energy while wishing for the victory of the Doosan Bears." She posted on Doosan's Instagram: "I really want to throw well." Nayoung called it meaningful timing. "I am excited to visit Jamsil Stadium in this meaningful year of I.O.I's 10th anniversary."

The baseball appearance landed during an active comeback. I.O.I dropped mini album 3 I.O.I : LOOP on May 19—their first new music in nine years since disbanding in 2017. Nine of the eleven original members showed up. Joo Kyulkyung and Kang Mina sat out due to scheduling conflicts. The nine who participated: Jeon Somi, Kim Sejeong, Choi Yoojung, Kim Chungha, Kim Sohye, Im Nayoung, Jung Chaeyeon, Yoo Yeonjung, and Kim Doyeon.

갑자기 hit #1 on Melon TOP100 as of June 2 and landed at #3 on the YouTube Music weekly chart. The group ran a three-day solo concert from May 29 to 31, with the final night selling out. An Asia tour is still coming.