The Backstreet Boys became hugely popular in Europe and the U.S in the late 1990s, and Carter gained fame, becoming known as the "heartthrob" of the group. He (Littrell) is the youngest, joining the group at twelve years old. On tour, he played drums and guitar. Carter had become a prominent lead singer in the group, though all five members sing lead on each album.
https://en.wikipedia.org/wiki/Backstreet_boys