We've all heard rumors about how Martha Stewart has fared in her new life behind bars. But now the ultimate Martha insider, her business partner, is sharing some surprising secrets, only to "Extra."

Susan Lyne, head of Martha Stewart Living Omnimedia, told us that Stewart is doing just fine. And although it's difficult to imagine the multi-millionaire behind bars, Lyne told us, "She is very comfortable in her skin there."

"She's made real friends down there," Lyne continued. "She empathized with a lot of these women, what they go through there."

As far as a day in the life of Martha in prison, Susan revealed that the domestic diva is up at 6 a.m. every day hitting the gym for an hour. "She's in great shape," Susan revealed. "She's been working out and she cleans all day for 17 cents per hour. But I've never heard her complain once, and I think now, with only eight weeks to go, she's in particularly high spirits."

Martha must also be excited about the launch of "Everyday Food," a show she produced prior to prison about preparing meals in 30 minutes or less. It premieres this weekend on PBS,

And there are even more Martha projects in the works. "She's more eager to get back to work," Lyne told us. "She has a thousand ideas."

Those ideas include a show with reality TV master Mark Burnett, who knows all about working with "Survivors." "She's also now a survivor," Lyne insisted of Martha. "She's been through an experience that gives her wisdom about life."