Kristen Bell will appear in the Gossip Girl finale.

The Forgetting Sarah Marshall actress, who recently revealed she is expecting her first child with her fiance Dax Shepard, voices the villainous titular character and although she has never appeared on screen in the show before, TV Line reports she will be featured in the December 17 hour long special.

On Friday, Bell tweeted: ''The saddest day I've had in a while...Last day on #gossipgirl Ill miss you, you snarky bitch!''

Kristen got engaged in to Dax, her co-star in When in Rome and Hit and Run in 2009, after dating for two years.