After a three-year hiatus, the Wonder Girls returned last week with their new album Reboot, led by the catching 80's-inspired lead single "I Feel You." For one of their first TV appearances to talk about the group's reinvention as a band, Yubin, Yeeun, Sunmi, and Hyerim appeared on Yoo Hee Yeol's Sketchbook to perform and open up about their latest project.

During the Aug. 8 episode of the KBS2 music talk show, host Yoo Hee Yeol asked the group about their band concept, which the members had previously revealed during an interview for SBS's One Night of TV Entertainment, is their biggest fear since they are stepping out of their comfort zones and promoting in an unfamiliar way.

"There have been people who were skeptical about how well you would do. You must have been scared," said Yoo Hee Yeol.

"[We] were really scared," said Yeeun, who plays keyboard in the group. "We worried about that when we first started this."

"No matter how hard we try, how could we battle people who have been doing this for 10-20 years? We wouldn’t even be able to say we are good," she added.

But Yeeun further explained how the fear gradually subsided as they kept practicing and rehearsing together. 

"But the music became more fun as we prepared," Yeeun explained. "We had good days and bad days, but we had fun listening to everyone’s emotions being portrayed through the sounds of our instruments. Then we thought about how we could share this fun with the public."

The latest Wonder Girls single "I Feel You" was composed by their agency's CEO, Park Jin Young and is the title track for their third studio album, Reboot.

After three years without any promotions, Wonder Girls reconnected as a four member band group with Yubin playing the drums, Hyerim as the guitarist, Sunmi on bass guitar, and Yeeun on keyboard.

Wonder Girls performed the band version for two of their previous hit singles and "I Feel You" during the Sketchbook broadcast.

Wonder Girls; "Nobody"

Wonder Girls; "Tell Me"

Wonder Girls; "I Feel You"