AceShowbiz -

Jennifer Morrison leaves behind her uptight role on "House M.D." to guest star as a cute but "a little bit crazy" nature lover on "How I Met Your Mother". The first clip from the episode she's appearing in has been released via EW, showing her character Zoey explaining to Ted how determined she is in saving the world from destruction.

The episode airs Monday, October 18 under the title "Architect of Destruction". Ted becomes conflicted about pursuing his dream job of designing the new GNB headquarters after meeting a hot girl who's passionate about saving the landmark building that is being torn down to make room for it.

Speaking of the possibility of Zoey being the Mother, creator Craig Thomas said, "Without giving anything away, it's a very, very big character who influences Ted's life quite a bit, so we were being very picky with who we cast. We'll see Zoey become a fixture of this group's world."

Morrison herself admitted that she's a huge fan of the show. "It feels natural to be here," she told TV Guide. "I was in Dallas playing a delusional killer on an episode of [NBC's] Chase when they called for me to come read with Josh [Radnor]." Thomas revealed that Morrison is here to stay a while, saying "We're talking about seeing Zoey's house, and she'll become part of Ted's Thanksgiving Day, much to his chagrin. And I can tell you she's in our season finale. But whether Jennifer's the mother, I just can't say."