SECRET NUMBER is only one day away from making their debut!

On May 18 KST, their agency Vine Entertainment unveiled the tracklist for their debut single album 'Who Dis?.' According to the tracklist, the album not only features a title track of the same name, but B-side track "Holiday" as well. 

Meanwhile, the five-member girl group is set to make their debut on May 19.

Check out the tracklist below, and stay tuned for 'Who Dis?'!