An enthusiastic monkey (or maybe a chimp [or possibly an ape (but definitely not a gorilla)]) is trying desperately to be center of attention on the set of CBS’ How I Met Your Mother.

[The following article contains some spoilers.]

The simian (that seems safe), wearing a hygienic and jaunty diaper, is hopping around and smiling. Mostly, though, the primate is being upstaged. Instead, everybody is preparing for a wedding.

It’s late September and one corner of the show’s stage on the 20th Century Fox lot is decorated like Shelter Island, a town at the eastern end of Long Island. I’ve never been to Shelter Island, so I can’t vouch for its accuracy. The wedding set actually looks like an unholy combination of a cult compound and a stage from the episode where the Bradys went to Hawaii. Think of it as Tiki-Moonie Chic.

In this Monday’s (Oct. 20) episode, Ted (Josh Radnor) and Stella (Sarah Chalke) decide take advantage of the nearly-discarded wedding pieces when Stella’s sister’s (Daneel Harris) nuptial plans fall through. That means getting everybody together in three days and hashing out whether or not it’s acceptable to have exes at your ceremony.

So does this mean that Stella and Ted are ready for their happily ever after? Can we finally start calling Stella the mother of Ted’s future kids? Or will complications ensue?

"How much am I allowed to say?" Chalke asks nervously. "You’re stressing out the bride on her wedding day. That’s not allowed. I have much more important things to think about, like whether the flowers are going to be in the proper arrangement in my bouquet."

I can say that Chalke is sitting across from me in a white Nicole Miller gown. I can also say that in the shot I just witnessed, a priest-type-figure said "Please welcome for the first time, Ted and Stella Moseby." How I Met Your Mother is a show prone to visualizing fantasies and hypotheticals, so you probably shouldn’t draw any conclusions.

Chalke actually looks far from stressed about playing out her possible wedding vows.

"It’s really fun, actually, yeah," she laughs. "I mean, we haven’t done them yet on this particular day, but it’s fun to get all dressed up and wear one of these…"

She holds out a hand and raises a finger to showcase a large presumably paste gem.

It’s very impressive.

"Thank you, I think he did very well," Chalke says.

For Radnor, the pleasure has been in playing Ted’s spontaneous and romantic side with Stella, watching his character grow even in his fourth season.

"He’s like everyone, he takes two steps forward, three steps back or three steps forward, two steps back," Radnor explains. "That thing with [Ashley Williams’] Victoria was kind of a big fantasy in a way and then they got slapped in the face with reality. The Robin thing was much more real, but also had its own challenges, the competing things that those characters wanted. This one feels like, it feels very real, but also, again, like life-things happening."

He continues, "They don’t know where they’re going to live. She has a daughter. There’s this other guy in her past. There are a lot of things going on that make it kind of high-stakes immediately, but he pushes through because he really loves her. I don’t know. I think it’s nice to play a guy who’s maturing. It’s not like the Ted you saw in the pilot will be the Ted you see in the end, which is often the case with series television, where characters don’t change that much, where you kind of have a template that you’re working with. But this show is about growth, so I’ve been allowed to change, which is fantastic."

Radnor also has enjoyed playing opposite Chalke, whose first guest starring appearance on the show was as close to last minute as the TV world gets.

"She came on the show it felt like she had never not been here and it’s not an easy thing to do," Radnor raves. "This is a pretty intense and tightly knit group of actors we have here. I just think she had the right energy for it, she had the right sense of humor, the right whatever that just made her a perfect addition to the cast."

Radnor says he doesn’t pay much attention to online scuttlebutt about whether or not Stella will turn out to be the eponymous mother, just putting his faith in the show’s writers.

"I stay away from all of that fan chatter unless someone comes up and talks to me, because I find it overwhelming and kind of strange to look into all that," he says. "Yeah, I don’t know. I have great faith in the writers as knowing how to tell this story much better than I could ever construct it. So I’m sure they’ll come up with something great."

Chalke agrees.

"Even when I came back to do the first one of these four, I had no idea what we were going to be shooting next," she says, comparing the degree of anything-can-happen uncertainty to her gig on Scrubs. "I don’t even know what happens next week! All I know is that I’m sitting in this little thing right now, but I don’t even know what happens next week."

How will the wedding episode end? And what’s with the monkey? You’ll have to tune in for Monday’s HIMYM to find out.

And after you’ve seen what happened, see what Radnor and Chalke had to say about what went down.

Posted by:Daniel Fienberg