From Entertainment Weekly:
"I'm fairly certain this calls for a Hallefreakinglujah!
Greg Daniels, the big boss behind The Office, just confirmed for me exclusively the best news ever: Amy Ryan will be reprising her spectacularly popular role as Holly Flax, soul mate to Steve Carrel's Michael.
"She will come back," says Daniels. "We haven't written it yet, but we're discussing her coming back for the season finale. We're hoping she'll be available."
Daniels went on to say that he's "very open" to working out a more permanent Office arrangement with Ryan. "Because [Michael and Holly] have such a deep connection, I don't think she can blow in and out every so often," he explains. "It would be too hard for him as a human being. So, we're hoping to find some very significant things for them. And if we can get her to sign on for a really long period, we'll do it."