Jennifer Morrison has three words for you: "I don't know."

Ever since her guest arc as Zoey on How I Met Your Mother DVD was announced last month, the actress has, understandably, fielded the same question over and over again: "Are you the mother?"

"It's not even that I can't say, but I just have no idea!" Morrison tells "It's always so funny because people think we have information that we don't, you know? I have no idea and I'm glad I don't know because I'd rather not have to lie about it."

What the former House star does know is that Zoey is going to be a "very important and large part" of Ted's life. How large? Morrison is currently contracted for 13 episodes — including the season finale that will feature a wedding — which would eclipse the nine-episode output of Sarah Chalke, who played the last important gal in Ted's life, his ex-fiancée Stella.

But it's not going to be all romance all time — or even initially — between Zoey and Ted (Josh Radnor) during Morrison's run. An activist, Zoey meets Ted in Monday's episode, and they get along swimmingly until she learns that he's slated to design the new Goliath National Bank headquarters in the place of a historic landmark she's trying to preserve.