1990s' dance group�R.ef has returned. The group�appeared on May 18th's airing of 'Yoo Hee Yeol's Sketchbook - Youth Night 2', and proved their still-growing skills and undying popularity.

'Youth Night 2' is the second '90s special aired after the success of the first in March.�Other top stars from the 1990s who guested on the special include�Shin Seung Hoon,�Turbo's�Kim Jong Kook,�HaHa,�Cool's�Lee Jae Hoon and�Kim Sung Soo,�So Chan Hee, and�Sung Jin Woo. miss A's Suzy also guest starred, filling in for�Yuri of Cool.

With the exception of Park Chul Woo, members�Lee Sung Wook and�Sung Dae Hyun performed together as R.ef for the first time in 14 years, and pumped up the audience with their talented dance moves and vocals.

This performance marks the�beginning�of Lee Sung Wook and Sung Dae Hyun's comeback preparations. Apparently, the two are receiving many love calls from famous composers like�Joo Young Hoon.

Source & Image: E Today via Nate