SEOUL, South Korea -- Japanese pop sensation ARASHI has a big surprise for fans as they near their planned hiatus at year's end: a collaboration with Bruno Mars on their first all-English single.The band told The Associated Press the multi-Grammy Award-winning musician delved into their back catalogue to understand their unique sound while working on the single that was released last week.“He took into consideration that we are going on hiatus,” said Jun Matsumoto, adding he feels their song,