"Holler" is a song recorded by the sub-unit TaeTiSeo and is the sub-unit's lead single from their second EP which shares the same name. It is also the first track from that album.
In an interview with "The Celebrity", Tiffany described Holler as "a rhythmical song that has a big brass sound that stands out with a funky groove, soul, and is overflowing with energy". Its music video was released on SM Entertainment's official Youtube channel on September 17, reaching 3 million views within a 3-day period, and becoming number 1 on YouTube's weekly "Top 20 K-Pop Music Video Chart", as well as on the weekly charts of two other Chinese online video sites, iQiyi and YinYueTai.
The song was initially given to Japanese singer Mizuki Watanabe under the title "Hello Me!", which was a B-side of her 2007 single, "Best Friend".