Wonder Girls further established themselves as one of the top girl groups in the country with the hit singles "So Hot" and "Nobody", which were released in 2008. After being released as a single in the United States in 2009, "Nobody" charted at number seventy-six on the "Billboard" Hot 100, making Wonder Girls the first South Korean group to enter the chart. The group began their entry into the American market the same year as an opening act for the Jonas Brothers' World Tour, performing English versions of their songs.