Gwen Stefani, Blake Shelton: Adam Levine Busts their Chops on 'The Voice'

Blake Shelton gave Adam Levine an opening on "The Voice" Monday night, and Adam seized the moment by poking fun at Blake's relationship with Gwen Stefani.

Here's the context ... Gwen was Craig Wayne Boyd's coach during Season 7, and got him to cut his hair. Gwen ended up letting Craig go, Blake took him and Craig won.

Now watch the clip ... Blake's doing a call back to Season 7, but Adam is lying in wait and not only made it seem like Blake was referring to his relationship with Gwen, he even mocked her laugh.

Adam's funny.