In 2010, Jung was featured on Narsha's solo album "NARSHA", for the song "I'm in Love". In 2011 he performed in the US with Trace Bundy, and also toured Scandinavia and Japan. In 2012 he collaborated with 2NE1, creating acoustic versions of the group's hit songs "Lonely" and "I Love You". Later in 2012, he participated in a live stage with BIGBANG's G-Dragon, where they performed "That XX". He performed "I'm Yours" with Jason Mraz, who described Jung as "amazing" and his "hero", in 2013. Jung played Ahn Hyeok in the 2011 Korean movie, The Suicide Forecast.