VIXX LR appeared on SBS radio show, 'Kim Chang Ryul's Old School,' on September 2, where the DJ Kim Chang Ryul brought up the popularity of Leo's '4-stage high note' from their song "Beautiful Liar."

"Isn't it hard?" he asked, and Leo admitted, "Honestly, it's really hard.  It's too high. However, when we promote, Ravi pressures me quite a lot by saying, 'Hyung, you're going to show them today, too, right?'"

SEE ALSO: U.S. Plane Crash that killed 67 people included two Korean American figure skating prospects

Taken aback by this sudden bomb, Ravi said, "I didn't order him to every time."  Leo said, "Not every time, but he orders me even during rehearsal," making everyone laugh.  Then, he added, "Although I say this, once I do [the '4-stage high note'], I'm happy with myself.  I feel like I'm bringing to life Ravi's energy, so it makes me feel good, too."

Listen to his super impressive '4-stage high note' below!