AceShowbiz -

Britney Spears did her own promotion of "Glee" appearance by posting a picture of her on the set. The singer, who has been working out in the gym and showed a toned body, announced via her Twitter that she began filming her cameo on Wednesday, August 18 afternoon.

"About to do my first shot of the day for Glee tweeties! Here we goooo!" she wrote earlier that day. An hour later she updated her fans with a picture of her in a formal suit and glasses. The accompanying message says, "What's up GLEEKS? Having so much fun on set!! Can't wait for you guys to see the episode!"

Britney would appear in an episode called "Britney/Brittany" where John Stamos is also making a guest appearance as a dentist. The Glee club members visit the dentist, are induced in ether and have dream sequence with Britney in it. Heather Morris' Brittany is up front and center in this episode, as Murphy put it, "Also at the heart of it, it's a show designed to show off the skills of Heather Morris."

The second episode of season 2 is directed by the series' creator Ryan Murphy, featuring at least six of Britney's songs. "We're sort of doing an episode about not only her music, but about her public image," Murphy told People.