Gino DePinto, AOL . When it came time to choose Christmas songs to record for their recently released holiday EP, pop group Big Time Rush went with a new tune, 'Beautiful Christmas,' and a festive classic, Mariah Carey's 'All I Want for Christmas Is You.' "Honestly, I think what they did was pick the hardest Christmas songs and were like, 'Boys, can you do this?'" BTR member Carlos Pena, Jr. tells AOL Music. "Like, how do four dudes cover Mariah Carey?" Kendall Schmidt says in agreement. "It was hard." "It's a hard song to recreate, but it was a challenge and we were definitely up for it," Carlos says. The boys of Big Time Rush, who visited AOL Music's studio for an exclusive acoustic performance, can all appreciate the talent of a pop icon like Carey -- and the success of the boy bands that preceded their own careers. As Carlos says: "I was, and definitely still am, a Backstreet Boys and 'N Sync fan....