Some of Korea's top stars have come together to promote a campaign for a cleaner, greener environment. The staff from Allure magazine have announced that they will be holding a '2011 Allure Green Campaign' at the Seoul Namsan Tower in commemoration of Earth Day on April 21st. The 4th 'Allure Green Campaign' garnered an impressive variety of top celebrities for the event, including last year's celebrity participants Lee Hana, Yoon Sang Hyun, as well as singer Lee Hyori and Brian Joo, and actresses Hong Soo Ah, Kim Sa Rang, Lee Yoon Ji, and Jun Hye Bin. Additionally, these stars participated in a photo spread for this month's issue of 'Allure', which will be themed specially for the 'Green Campaign'. Check out some of the pictures from the pictorial down below! [gallery columns=4] Source: Newsen via Nate