She said: "It's like getting into you pyjamas (wearing the tracksuits). I now probably have 30 tracksuits. The wardrobe designer likes to get a new batch every seven or eight episodes and she's crazy with the colours. I have a fuchsia one, a lime green one, they're fabulous."
Jane's character Sue is famed for her tough-talking, no nonsense nature and the actress has revealed viewers will soon find out why the cheer-leading coach has such a cold exterior.
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In an interview with the Metro newspaper, she said: "We're going to get a piece of why she's mean in this series. We find out that Sue herself may have been a lover of musical theatre as a child. And perhaps someone badmouthed her. I don't know."
Although she is world famous because of her role, Jane insists her TV stardom doesn't impress her nine-year-old stepdaughter Haden - who she raises with her wife Lara Embry.
The actress has taken Haden to numerous glitzy events and although she is grateful she isn't dazzled by celebrity.
Jane revealed: "Kids adjust so easily. I've taken her to premieres of really big hit movies and she appreciates them. But I pick her up from school and the kids, in the beginning, were like, 'It's Sue Sylvester.' And now I'm just another mom."