Before her official debut, Ailee appeared on MBC's Chuseok special program, "Singers and Trainees," sharing the stage with her mentor, Wheesung. Then just a rookie, Ailee really stole the show with her powerful performance of Beyonce's "Halo."

Chanyeol and D.O. made fans swoon with this acoustic cover of B.O.B.'s "Nothin on You" on the radio show, "Kiss the Radio." It showed a different side to the more upbeat, dance songs their group is best known for.

As IU sang in her latest hit song, "Palette," she sure does love Corinne Bailey Rae. Since her debut, IU has proclaimed the British singer-songwriter as her idol. So imagine how mind-blown she was when she got to perform with her idol at her concert in Korea!

Jo Kwon's truly channeled Lady Gaga -- from his outfit to makeup and even the killer heels -- in this jaw-dropping performance of "Born This Way" on "Golden Tambourine." Jo Kwon also delivered a powerful message to haters who criticized him for cross-dressing on stage, quoting Gaga's words: "Don't be a drag ? just be a queen!"

Yuju proved why she's the main vocalist of her group with this cover of Taylor Swift's hit song on "Kiss the Radio." With her wide vocal range, she sang the song beautifully with more ease than the original singer herself.

No one can come close to matching Beyonce's epic performances, but Hyorin -- who has in fact been hailed as the "Beyonce" of Korea -- did a stellar job here. Her powerful vocals were unshaken by the rigorous, sexy choreography she slayed simultaneously.

Jessi and Hyorin were guests on the "Fiery Summer Swag" episode of "Yoo Hee Yeol's Sketchbook" and they certainly lit up the stage with this duet performance. Like the close friends that they are, they fed off each other beautifully and enhanced each other with their unique, husky voices.

Dean's smooth R&B flow really shined in this acoustic cover of Drake's "Hotline Bling."

Lee Hi blew the "K-Pop Star" judges away with her audition performance of Jazmine Sullivan's "Bust Your Windows." Everything from her rich, husky tone to her R&B groove and even her sultry facials perfectly captured the essence of this song, which tells a revenge tale of a woman who caught her man cheating.

Their voices are so distinct but altogether, it's a harmony that will surely make you swoon -- especially when they're singing a medley of classic love songs.

Who wouldn't "stay" after listening to Lucky J's version of this song? Ssen-unnie Jessi showed a very different side to her charismatic, roaring performances as a rapper with this duet of Rihanna's hit song with fellow Lucky J member J-Yo.

The K-pop queen performed a beautiful acoustic cover of Rihanna's version of Eminem's hit song, joined by pianist Yoonhan.

It's no wonder why Henry is called a musical genius. Henry added his own unique twist, passionately singing Zayn's sexy slow jam while playing the piano. It's a shame it's only a minute and a half long!

The girl group awed with this awesome cover of Maroon's 5 pop rock song. They truly made the song their own with their refreshing, powerful vocals and hard-hitting choreography.

LUNFLY has released some awesome covers, also filming their own music videos. But Sam and Yun's soothing, sweet vocals really enhance Ed Sheeran's romantic song. This one will make you melt!