Britney Spears' Best Pre-'Glee' Comedy Moments Before she hits up 'Glee,' relive her small-screen history.

Tuesday night's (September 28) "Glee" episode is all about Britney Spears. While fans and the show's stars are excited to see the singer light up the screen in the appropriately titled "Britney/Brittany" episode, it's hardly the first time Spears has performed for a laugh on the small screen (and we're not talking about her docu-series "Britney & Kevin: Chaotic").
Spears brought the funny in a show-opening appearance on the 2009 VMAs, her top 10 list on "Late Night With David Letterman" and on "Saturday Night Live," especially during her stints as the show's host in 2000 and 2002.In 1999, Britney Spears stopped by "Sabrina the Teenage Witch" to teach Melissa Joan Hart a lesson or two about loneliness, fame and the proper way to do choreography. The duo also hooked up for Spears' "(You Drive Me) Crazy" video from the soundtrack for Hart's movie "Drive Me Crazy," which featured "Entourage" star Adrian Grenier.Spears was one of the many pop stars to stop by "Will & Grace" when she made an appearance on the show in 2006. She showed off her Southern accent and comedic flair as closeted lesbian Amber Louise.The singer proved she was funny once again when she appeared on "How I Met Your Mother" in 2008. Her People's Choice-nominated cameo (she was up for Favorite Scene-Stealing Guest Star) had fans rooting for her again after a difficult period in her personal life. She hit the small screen as Abby, a receptionist with a grudge against Barney (Neil Patrick Harris) after he forgot to call her after they, uh, went out.