HaSeul (or LOOΠΔ & HaSeul) is the third single album from South Korean girl group Loona's pre-debut project.

It was released on December 15, 2016, by Blockberry Creative and distributed by CJ E&M.

[1] It introduces member HaSeul and contains two tracks, her solo "Let Me In", and a Christmas collaboration song between her, HeeJin and HyunJin, titled "The Carol".

Music videos for both songs were released simultaneously on December 15.