Leighton Is Replaceable!

Leighton Meester‘s prospects of making it in the music business while still acting on Gossip Girl are slim to none! She’ll just bee too busy to properly promote and tour a record.
Like last night!
Meester is featured on Cobra Starship‘s song Good Girls Go Bad, written by Kara DioGuardi and Kevin Rudolf. The band performed the single on The Tonight Show WITHOUT Leighton.
In her place, they had British singer Estelle sing her parts!
Check it out (above).