'Glee': Is Kitty Sabotaging Marley? (Exclusive Video)

After losing the lead in McKinley's rendition of Grease, Kitty may not be done with Marley on Fox's Glee.

In an exclusive clip from Thursday's "Glease" episode of the Fox musical, Kitty's (Becca Tobin) claws may be coming out again as the bitchy Cheerio appears to be the only one to notice Marley's (Melissa Benoist) apparent weight gain as her fitting for the Sandy costume doesn't go according to plan.

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But is it stress bloating, as Tina (Jenna Ushkowitz) suggests or is Kitty playing into Marley's insecurities after poking fun at her mother's (Trisha Rae Stahl) weight and warning Ryder (Blake Jenner) of what could be in store for the New Directions newcomer?

"We will see more of her back story," Benoist told THR. "It's been amazing working with Trish and developing that relationship. It gets more and more touching. Marley deals with a lot of self-consciousness and her mom is such a rock for her. You'll definitely see more of that."

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"Marley's biggest obstacle is her image of herself," she said. "She has a lot of personal battles to conquer before she can really reach out as much as she wants to to Jake (Jacob Artist)."

Check out the clip above and hit the comments with your thoughts on if you think Kitty is responsible for altering Marley's Sandy costume. Glee airs Thursdays at 9 p.m. on Fox.

Email: Lesley.Goldberg@thr.com; Twitter: @Snoodit