Love of Siam (movie, 2007)

Two young boys are best friends living quiet family lives in Bangkok. Their lives are disrupted when one boy's older sister goes missing on a jungle trip. The shattered family moves away, separating the boys. Years later, now in their late teens, the boys meet again. One of them is now the leader of an aspiring boy band whose managing assistant bears a striking resemblance to the lost sister. The boys must deal with their family and social lives and their feelings for each other.