'Glee' preview: It's Britney, Gleeks!

Cast members and even Spears herself have dropped hints about what to expect in the much-hyped tribute episode. What we know so far:

1. The “B/B” song list includes “Toxic,” “Stronger,” “…Baby One More Time,” “Me Against the Music,” “Oops!… I Did It Again,” and “I’m a Slave 4 U.”

2. The “Santana and Brittany at the dentist” scene is definitely worth the watch.

3. Sue Sylvester will not be amused when she learns what New Directions is up to.

4. John Stamos only improves with age. Related content:

Are guest stars going to ruin 'Glee'?

Sneak peek: ‘Glee’s’ ‘Britney/Brittany’ episode

Slideshow: Britney's most memorable style moments

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