(CNN)K-pop fans can breathe a sigh of relief, with BTS here to stay -- for a few more years, at least. Fans have long worried that the boy band, arguably the biggest in the world, could see their success derailed by South Korea's mandatory military service. But on Tuesday, the parliament passed a bill allowing pop stars -- such as BTS -- to defer their service. Previously, the law allowed special exemptions for top artists, athletes, and musicians -- for instance, those who have won classical music competitions -- but not top K-pop stars.