OMFG! Two of my favorite shows are about to collide — and it sounds like it’s going to have us ROFWL!

Gossip Girl frenemies Leighton Meester and Blake Lively have closed a deal to guest-star in a November sweeps episode of NBC’s increasingly stunt-happy 30 Rock, sources confirm to me exclusively. The dynamic duo will play — prepare to laugh ’till you piddle — former high school classmates of Liz Lemon’s in a flashback sequence that reveals a shocking and deeply ironic truth about Tina Fey’s morally superior alter ego: She was a Mean Girl!

Gen. Ius.

The Gossip-inspired flashback coincides with Liz’s 20-year high school reunion, which means we’re also going to meet the adult versions of Meester and Lively’s characters. (In a kicky twist, Rock execs are talking to Blake’s older sis, Robyn Lively, about playing the latter part.)

C’mon, admit it: This is 10 times more exciting that Jennifer Aniston.

Now for something totally unrelated, have you ever had a burning desire to beat me at something? Anything? Well, with our just-launched Emmy Prediction Game, you’ll finally get your chance! It’ll never happen, of course, but at least you’ll have fun trying! (Additional reporting by Lynette Rice)

Source: Ausiello Files