They're most likely one of the biggest pop acts you have never heard of, but Girls Generation, a nine-member Korean pop group that came together in 2007, have since become a national phenomenon.

Their 2009 hit "Gee" is the longest-running #1 song on the Korean Broadcasting Charts; their self-titled album released in Japan in June went double platinum, a first for a Korean girl group; and their latest music video, "The Boys," has racked up nearly 12 million YouTube views in just one week.

Girls Generation (a.k.a. Soshi or SNSD by their international fans) are now gearing up to take over the U.S. airwaves. After releasing their third studio album The Boys last month in Korea and then worldwide, the ladies have signed with Interscope Records. On Monday, all nine girls stopped by the MTV Newsroom and talked to us about their success, including performing to a sold-out crowd at Madison Square Garden this week alongside several other Korean pop acts.

"Performing at Madison Square Garden is a real honor, so we had a lot of fun," Jessica told MTV News.

"It was epic," Tiffany added.

During the performance the girls sang, for the first time, the English version of "The Boys." The track has a heavy beat and a radio-friendly sound, showing off not only their strong vocals but their rapping skills.

"It went pretty well," Jessica said of "The Boys" performance. "They all sang along, so we were really happy to sing it in front of our fans for the first time and we thank everyone for singing along."

So with "The Boys" single about to hit the States and the video already out, will the girls work on a full-length English album?

"Yes!" Tiffany revealed. "Our U.S. maxi single will be released November 19, it will be in stores, and we're just as excited as anybody else. We haven't started on a full-length album, but we're kicking off with this maxi single and hopefully it will lead to a full-length album."

While the girls are still expanding their Stateside fanbase, they were overwhelmed by the outpouring of love from fans during their visit. "This whole situation itself has been pretty surreal," Tiffany admitted. "So we are just very fortunate and we're just really excited to be able to meet our fans here in the East Coast and in the U.S."

Jessica chimed in, "We're just very lucky to have all these fans supporting us."

Girls Generation made MTV Buzzworthy's list of must-hear songs this week! Who else made the cut?