<P> NBC broadcast the two - hour America's Got Talent Holiday Spectacular on December 19, 2016, hosted by Cannon with performances by Grace VanderWaal, Jackie Evancho, Andra Day, Penn & Teller, Pentatonix, Terry Fator, Mat Franco, Piff the Magic Dragon, Olate Dogs, Professor Splash, Jon Dorenbos and others, and featuring the Season 11 judges, including Klum, who sang a duet with Season 11 finalist Sal Valentinetti . The special drew 9.5 million viewers . </P> <P> Since the show began, its ratings have been very high, ranging from 9 million viewers to as many as 16 million viewers, generally averaging around 11 million viewers . The show has also ranked high in the 18--49 demographic, usually rating anywhere from as low as 1.6 to as high as 4.6 throughout its run . Audition shows and performance shows rate higher on average than results shows . </P> <P> Although the show's ratings have been high, the network usually keeps the show's run limited to before the official start of the next television season in the third week of September with some reductions or expansions depending on Olympic years, where finale ratings are usually lower due to returning programming on other networks . </P> <P> The highest rated season in overall viewers to date is season four (2009). The most - watched episode has been the finale of season five (2010), with 16.41 million viewers . The series premiere and an episode featuring the first part of Las Vegas Week in season six (2011) have each tied for highest rating among adults 18--49, both having a 4.6 rating . </P>

When are the next auditions for america's got talent