Wheesung has also done a large number of collaborations, as well as writing and composing songs for other artists.
He left after the band's first album debut, citing musical differences between himself and the other members of the band.
Wheesung left YG Entertainment after his contract expired in March 2006.
He signed a new contract that is reportedly worth 1.5 million won with his new company Orange Shock Agency.
This was their first collaboration since the breakup.
Yang Hyun-Suk has produced hugely successful artists under his entertainment, most notably Jinusean, 1TYM, Se7en, Big Bang, and 2NE1.