Guest star Kate Hudson's character Cassandra puts Rachel in her place and shows off her musical talent in promos for tonight's season premiere episode of 'Glee' called 'The New Rachel.'

Hudson plays Rachel's intimidating dance instructor in New York. She tells the class, "I may not be a wide-eyed ingenue anymore, but I can still dance circles around any of you." Hudson proceeds to deliver a dance number for a medley of Jennifer Lopez's 'Dance Again' and Lady Gaga's 'Americano.'

In one clip, Hudson describes her terror about having to learn pages of dialogue in just two days before shooting. Lea Michele says of Hudson, "The way she can sing and dance is literally out of this world. I told her today, 'You are Britney Spears, circa-2000, 'I'm a Slave 4 U,' at her prime'... What a way to kick off our fourth season."

In a separate clip Michele explains where Rachel is at the start of Season 4: "She's basically all alone. She misses Kurt, and she doesn't really know what's going on with her and Finn, so she's sort of a little fish in the big city." The promo introduces Dean Geyer's new character Brody, who Michele calls "the only guy who Finn has had to compete with for Rachel."

Meanwhile, Kevin McHale and Darren Criss report that New Directions are smaller but still going strong, and they have several talented new members joining, including Marley, who seeks to replace Rachel.

The Season 4 premiere of 'Glee' airs tonight (Sept. 13) at 9PM ET on FOX.

Watch Kate Hudson Perform 'Americano / Dance Again'

Watch Behind-the-Scenes Footage from 'Glee' Season 4

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