SEE ALSO: B1A4 win #1 + Performances from January 24th 'Music Bank'!

Rain shared on his new Instagram, "Start of practice... Are we allowed to be like this ... Everyone is toast, Please look forward to it doodoong!! Bi...Jin...Ah... #rain#LAsong #BiJinAh", "We are ready ...^^", and "BiJinAh ... Will continue... To upgrade. 'Music Core' and 'Inkigayo' ~~ ke Please look forward to it."

The two veteran singers look like they're having a good time both on-and-off stage, getting fans grooving along with their cross between pop and trot music for "La Song". Rain, who is usually 100% charisma on stage, couldn't hold back his smile and laughter during their stage with Tae Jin Ah's hilariously cute moves.

Continue to get your 'la la la' on with Rain and Tae Jin Ah on 'Music Core' and 'Inkigayo' this weekend!