The cast of 'Glee' reunited on 'Drop The Mic' for a rap battle to end all rap battles.

'Drop The Mic' had a high school reunion recently, with some of the cast of 'Glee' rocking up and rapping out- and it got very personal, very quickly.

Amber Riley, Harry Shum Jr., and Becca Tobin battled it out against former co-stars Kevin McHale, Jenna Ushkowitz and Heather Morris, and embraced their teenage alter-egos one last time. Morris deals one of the most jaw-dropping burns, rapping to Tobin, "Becca, let me make sure I'm getting this right - I played the dumb blonde on 'Glee', you play one in real life." Ouch.

Check out the full blow-by-blow rap battle below.

In case you missed another notable 'Drop The Mic' rap-battle, make sure to check out Kirmit the Frog and Missy Piggy having their Muppet dis-off right here.