VIXX's Hongbin, NU'EST's Ren, BTOB's Minhyuk, and A-JAX's Seungjin gathered to form 'Boy's Day', making fans do a double take with their sexy transformation into girl group members for 'Music Core's 400th episode special later today!

SEE ALSO: 'Music Core' 400th episode to have special Boy's Day stage, performance by EXO & more

As mentioned previously, the prettiest members of boy groups that are currently promoting including BTOB's Minhyuk, NU'EST's Ren, VIXX's Hongbin, and A-JAX's Seungjin, formed the project boy group, Boy's Day, and will be performing "Something" with Girl's Day on the program.

The boys brought laughs from fans as they showed off their new looks for the upcoming special, evidencing just why they were chosen as the prettiest male group members. Hongbin and Ren also provided close up shots, giving fans a good look.

Stay tuned for the awesome collaboration stages on 'Music Core' 400th episode special today!