Wu-Tang Clan's next collab is gonna be really weird ... is what we'd say if this pic with ex-FBI Director James Comey was taken anywhere near a recording studio.

Thankfully, Ghostface Killah and Method Man were just backstage at the 'Late Show' Tuesday when they ran into Comey. Truth is, Meth and Ghostface have some pressing biz with Comey's old boss ... and might have hit him up for advice.

Attorney General Jeff Sessions currently has custody of Wu-Tang's album "Once Upon a Time in Shaolin" ... which the feds seized from Martin Shkreli.

We're guessing Comey told 'em he's not exactly tight with his old crew at the Justice Dept.