She's one of the "Bad Girls" all right.

In Tuesday's episode of the Seoul Broadcasting System (SBS) television program "Story On Women's Show," Lee Hyori confessed to once trying to sabotage an S.E.S. performance while she was a member of rival girl group Fin K.L.

"It was impossible not to feel jealous [of S.E.S.] at that young age," Lee explained.

Formed in 1997, S.E.S. is widely considered to be the first K-pop girl group to reach superstar status.

But to a young, ambitious Lee Hyori they were the competition.

"When S.E.S was on stage, they used a lot of bubbles, and many times, the Fin.K.L. members slipped because of it," Lee said.

"So I was waiting for an opportunity to come around, and it finally came during our 'White' promotions. It was a winter song and our props were snow sprays."

But the chart-topping solo artist said the stunt only backfired on her and the rest of her band.

"The dancers sprayed so much that the fake snow ended up going into our eyes and mouths, and sometimes our faces weren't even shown on screen because of all the snow," the "Bad Girls" singer recalled.

"But when S.E.S got on the stage next, they did so well."

The "Miss Korea" singer appeared with Lee Joon last week on the SBS program "Incarnation," where the MBLAQ singer admitted to being a super fan of Lee's former band.

"I really liked Fin.K.L," Lee Joon told Lee Hyori awkwardly.

When Lee Hyori asked him if he was afraid of her, Lee Joon responded that he was simply overwhelmed.

"I used to follow Fin.K.L around on promotions and stuff, so my feelings right now are so weird," the MBLAQ singer said.

"Who knew this could ever happen?"

Joon even confessed to having a dream when he was in high school about being on a beach with Hyori.

"It made me really happy," he said.

"I used to like Sung Yuri [of Fin.K.L] the best, but after that, Lee Hyori became number one."

Lee explained last week on the program "Hwasin - Controller Of the Heart" that she has her own tropical fantasy.

"I want to live in Jeju Island. Because I'm close to teacher Jang Phil Soon too who lives in Jeju Island, I found out about many hidden places, not just the tour places. So I thought that I should just buy the good land that I saw first and see what I can do with it," she said.

"I built a villa there so I've been going pretty often. If I get married, I can live there, but for now, it's a place I go back and forth in. I went with Lee Sang Soon recently as well."