American Idol fans are an unpredictable lot. In a surprise move, viewers voted off sweet Georgia underdog R.J. Helton Wednesday night. It was widely believed that Nikki McKibbin — coming off of an abysmal performance Tuesday evening — was a shoo-in to get the boot. Now, the contest comes down to four finalists: McKibbin, Kelly Clarkson, Tamyra Gray and Justin Guarini. Meanwhile, Fox's summer smash continues to pick up steam as it heads toward its Sept. 4 finale. Tuesday night's performance edition attracted a series-high 12.7 million viewers.