South Korea's biggest girl group finally made their comeback to the K-pop scene on Monday evening.
Girls' Generationstill reign supreme, with their lead single Mr.Mr. topping all music charts in Korea within an hour of its release.
But they have some stiff competition coming up almost immediately.
Despite their tremendous success, the nine-member Girls' Generation may see their thunder stolen by another A-list K-pop girl group.
On Feb 10, Girls' Generation, from SM Entertainment, had got their fans excited by dropping a 40-second teaser video that announced the release of their single on Feb 19, followed by their six-track mini album release, also titled Mr.Mr., on Feb 24.
Two days later, quartet 2NE1, from YG Entertainment, revealed that they would release their new 10-track album Crush online on Feb 24 as well, with the physical copy out a week later.
The dates promised a big showdown between two of Korea's most popular girl groups as they would go head-to-head in the music chart and music programme rankings.
The imminent fierce battle naturally set tongues wagging between their hyper-passionate fan bases as they questioned the groups' agencies' motives for pitting their prized acts against each other.
Then, adding to the buzz, SM Entertainment announced on Feb 13 that the release of the Mr.Mr. single would be postponed.
A statement from SM Entertainment read: "Computer files for the song's video were found to have been mistakenly deleted in the post-production process recently. The album release may have to be delayed if the deleted files are not recovered."
A company official added: "The deleted scenes are important for the video, so we're now checking if any restoration is possible. If not, we need to find ways to film the scenes again.
"In that case, we may have to delay everything from the release of the title track to online services to the first TV appearance."
Girls' Generation eventually released the single along with the album on Monday.
But just when music critics and fans thought the showdown was about to start, YG Entertainment pushed the release of Crush to Feb 26, calling it a "more special day as it is also the birthday of 2NE1's leader CL".
Addressing the prospect of battling their strongest competitor, 23-year-old CL said: "This is our first studio album in four years.
"Coincidentally, it turns out we are facing off with Girls' Generation during the same time period, but rather than viewing it as a competition, I have high expectations. Please have high expectations for our music."
2NE1 member Dara, 29, added: "(Girls' Generation) have a different style as compared to us when it comes to music. I hope we both do well."
Indeed, the single Mr.Mr. features an uptempo electro-dance tune while 2NE1's title track Come Back Homeis a mix of reggae, R&B and hip hop.
SM Entertainment revealed that the concept for the album is "classy" and "mysterious" rather than "sexy", adding: "We're going to show a transformation that only Girls' Generation can show".
Supporters of both groups are looking forward to the impending intense battle and rooting for their idols in the next few weeks.
2NE1 fan Jolene Lee, 21, told M: "I can't wait for them to perform live soon. I am very excited as they have not released a full-length album for almost four years."
A Girls' Generation fan, student Matthias Ng, 21, had a different view: "Girls' Generation has a much bigger fan base in Korea than 2NE1.
"I don't mean to be biased but I think they will win instead. Their new single is catchy, and I think they are going to perform very difficult dance choreography, so I am looking forward to it."