there was this manhwa where it was like the mc (whos a girl) was bestfriends with another ...

there was this manhwa where it was like the mc (whos a girl) was bestfriends with another girl throughout high school, but one day that girl bestfriend showed up as a boy and it turned out he was a guy all along but dressed as a girl and the mc was super shocked and the guy had a crush on her or something. i saw this in an ad a long time ago and im still curious if anyone knows it!!!! ლ(´ڡ`ლ)