AceShowbiz -

Having the privilege of presenting many guest stars, NBC's "30 Rock" makes use of the "Gossip Girl" popularity by signing in two of its cast for a cameo. Blake Lively and Leighton Meester who play Serena van der Woodsen and Blair Waldorf respectively will appear on the comedy show as guest-stars.

Entertainment Weekly's Michael Ausiello revealed exclusively that both stars have closed the deal for a November episode. Roles that they will be playing are the high-school mates of Liz Lemon (Tina Fey) who will support the insight to Lemon's place in the community while a student.

A source told EW that Lemon was a popular girl in her high school days, very much like a Mean Girls -type of bully. The flashback is brought in the episode where Liz attends her 20-year high school reunion, meaning there will be the adult versions of Lively and Meester's characters. Words are rive that Blake's older sister Robyn Lively is in talks to tackle the adult role.

Earlier this month, Jennifer Aniston was confirmed to make a cameo as Jack Donaghy's (Alec Baldwin) stalker, while Oprah Winfrey was said to be in negotiations to play herself.

The new season of "30 Rock" will air on October 30.