The daughters of Republican presidential hopeful Jon Huntsman have released a video in which they rap about his rivals to the beat of a Justin Timberlake song.

To the tune of Timberlake's Sexy Back, Libby, Addy, and Mary Anne Huntsman declare: We're bringing Huntsman back ... The rest of them is one big circus act.

The candidate's daughters have been vigorously campaigning for him on television and over the internet, and they have their own Twitter profile under the name Jon2012girls.

Their tweets from the campaign trail have earned them more than 15,500 Twitter followers. They tweeted Thursday's release of Huntsman's Back with the message, Spotted: Herman Cain rolling up in style to the Hilton Garden Inn in Manchester with a 6-car motorcade...jamming to this.

The video's release comes as the Republican candidates began to campaign more aggressively ahead of the start of the primaries in January. Huntsman has struggled to make an impression on the national scene. Mitt Romney has been in the lead of most polls until now, but rival Newt Gingrich is making a late surge, with other contenders Michele Bachmann, Rick Perry, and Cain falling back.

Huntsman, 51, is a former U.S. ambassador to Singapore, the U.S. trade ambassador under George W. Bush, and the ambassador to China in 2009. He has seven children in all. Two are adopted, one a girl from China and another a girl from India.

Check out the rap video here: