So Hot (3rd Project) is the second maxi-single by South Korean girl group, Wonder Girls. It was initially released on May 22, 2008 with the song "So Hot." Afterwards, the maxi-single was released on June 3, 2008. The single became an instant hit and quickly hit #1 on various online and offline charts.
In order to promote the single, JYP Entertainment first released teaser pictures of each member in May 2008, showing the Wonder Girls in their new "sexy image". Starting with Ye-eun, pictures were released on 5 consecutive days, ending with Ahn Sohee's pictures. Following the pictures, "So Hot" was previewed on their website. During this time, there were rumours that past member Hyuna would be returning to the group; JYP Entertainment confirmed that this was not the case.
"So Hot" was first given a digital release on May 22, 2008; the song topped online charts in the next few days. The full single was released on June 3, 2008, given the subtitle The 3rd Project. In addition to the title track, the single also contained new songs "This Time" and "You're Out" as well as the rap version of "Tell Me", which was unreleased until this point.
JYP Entertainment stated in June 2009 that "So Hot" would be the third English single for the group, after "Tell Me". On May 15, 2010, they released their 2nd American single "2 Different Tears" (also known as 2DT), which includes So Hot on the tracklist.
The Wonder Girls began their comeback performances on May 31, 2008 on MBC's Music Core, performing "So Hot" and "This Time". The members sported a brand new mature look, wearing leopard print outfits; future performances showcased varying outfits based around the print. A music video was produced for the song, showing the girls in various situations, with men instantly falling in love with them. "So Hot" became an instant hit and was the number one song on MBC's show Music Core and on SBS's Inkigayo for three consecutive weeks. Due to vocal chord problems, Kim Yubin lipsynched her parts, as per her doctor's orders, until the end of July 2008.