On September 25, San E posted a photo via his Instagram page with the caption, "#theunit kbs first get together with mentors."

The snapshot featured San E dressed in black alongside fellow mentors Rain, Hwang Chi Yeol, and Urban Zakapa's Jo Hyun Ah.

#hwangchiyeol hyungnim 'Generous'

#johyunah 'Always will be a 19 year old to me'

#rain hyungnim 'Le...legend

#sane 'hmmm...what am I? what do you all think?'

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Rain will be acting as an MC/mentor, including Hwang Chi Yeol as a vocal mentor who previously worked with junior idols.  Jo Hyun Ah will also be instructing participants.  Last but not least, San E will be greeting contestants as a rapper.

Meanwhile, 'The Unit' will feature various idol groups such as DIA, Boys Republic, LABOUM, Boyfriend, Dal Shabet, Hot Shot, BLACK6IX, Wassup, and much more.

#??? kbs ? ???? ??? ??? #??? ?? ??? #??? ?? ??? 19??? #? ?? ?...??? #?? ?....? ??? ???? ???? ? ???

A post shared by San E (@sanethebigboy) on Sep 25, 2017 at 10:28am PDT