Showrunner Steve Molaro talks with THR about what to expect from the not-so-happy newlyweds at the start of season nine.

For The Big Bang Theory diehards, this is the moment you've been waiting for.

The season nine premiere of the nerdy comedy from Chuck Lorre, Bill Prady and Steve Molaro will pick up in Las Vegas and feature Leonard (Johnny Galecki) and Penny's (Kaley Cuoco-Sweeting) nuptials. But that doesn't mean everything will be smooth sailing after Penny learned that Leonard kissed another woman during his North Sea expedition two years ago.

"Chuck and I had a long talk about [revealing the wedding before the premiere] and my fear was that it was going to start sound like they didn't [get married]," Molaro tells The Hollywood Reporter. "That was not a positive message — and we didn't want fans to feel like, 'Oh, they're going to pull the rug again and not do it.' There is so much more story beyond that moment that we decided to just let people know."

Here, THR has the exclusive first-look photos from Leonard and Penny's wedding as well as what could be the most awkward wedding night ever — all included in the season nine premiere.

"It's season nine and Leonard has been pursuing her since minute three of the series," Molaro says of why the time was right for the on-again, off-again couple to finally say, "I Do." "Even Penny, with all of her commitment issues, is in a mindset of, 'Are we moving forward with this or not? What are we doing?' And they do."

Below, Molaro breaks down what happens next for the newlyweds and how Leonard's North Sea "friend" Mandy (Melissa Tang) will impact the early days of couple's union.

Last names are typically part of wedding ceremonies. Will we finally learn what Penny's maiden name is?

Obviously with her getting married, she will have a last name and I think we've delicately dodged hearing her last name in the premiere. And I think it's done in a way that is very much based in the story. It'll make sense when you see it.

So Penny Hofstadter is now official?

Pretty much, yes! [Laughs.]

Given Penny's awareness that Leonard kissed another woman, was this marriage something she had to talk herself into?

A little bit, yeah. She thinks she's OK with it and she may not be.

It's so interesting because Leonard was on the sea and was drunk —

— and it was a few years ago, but it fluttered. It's the kind of thing that you wouldn't expect to happen and that can be a little jarring. I think when you're Penny, and you have an image that you've cultivated of a person for eight years now and those two things aren't aligning anymore — that can be a difficult thing to deal with.

How difficult is that going to make their wedding night like?

It's going to prove to be quite a challenge! [Laughs.]

Poor Leonard, he's waited eight seasons for this!

Well, no, he does have a hand in this! [Laughs.]

Leonard is clearly not out of the woods with Mandy. What will Leonard and Mandy's reunion look like? How might Penny respond to that?

Leonard will speak to her in a desperate attempt to put this fire out. This all goes down in the second episode. The topic of Leonard talking to Mandy or Penny talking to her or the three of them talking to each other comes up. The thought of maybe somehow interacting with her that this can all be put to bed is the impetus behind it.

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Is this something that's going to go away after two episodes?

Things will start to get better, not necessarily because of that, but Leonard and Penny are both invested in figuring out how to fix this.

Now that they've eloped, they still need to share the news with their respective families. What kind of responses can we expect?

This is going to be news to them because they eloped. Surprised is probably at the forefront of emotions for them. As for how they react, tune in and find out! We will be hearing and seeing Penny's dad, Keith Carradine, coming up since he hears the news of her marriage.

Given that they eloped and Howard and Bernadette's ceremony was on the roof, did you miss getting the chance to feature a formal wedding? Is that something we could see at some point down the road?

I think when you see the premiere, you will feel that it's satisfying. There's a really special moment, despite all of the things that are happening, that I think makes Leonard and Penny — and especially their vows — truly a magical moment that I'm really excited about.

How hard was it for you to write their vows?

Any time any big moments in the show are going on, tension rises in the writers' room, but I think we were all excited about this one idea and all on the same page, and I think it turned out well or better than we could've possibly hope for. Johnny and Kaley just killed it, it's so good. It was one of those things where I even called them before we were back [in production] just to tell them how excited I was about it.

Now that Leonard and Penny are married, the living arrangements have to shift beyond one night a week.

Living arrangements are definitely going to be confronted in the first four episodes. It's tricky, sure — Leonard and Penny need to move forward, but at the same time we have a broken-hearted Sheldon (Jim Parsons), who is sort of their little brother and child and it's tough to ignore that for them.

Will there be more bonding between Leonard and Sheldon now that they're in such different places? Sheldon needs Leonard more now than ever but Leonard needs Penny more.

That's exactly it: they're trying to all figure it out. We jokingly alluded to the fact that in some way the three of them are kind of married and I think the three of them will need to figure out how this is going to work.

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What about Leonard and Sheldon's discovery? In my mind, this is what winds up being part of the show's end game.

They're still involved in that. We've got so many other plates spinning right now that that's not one of the focuses early on in the season. But it will come back and will continue to move forward. And that's another way in which Leonard and Sheldon will continue to be "married."

What about Penny's acting career? Now that she's married, are we going to see her go back to that at all?

There are no plans at the moment. She's moving forward to pharmaceutical sales and seems to have found a thing that she's pretty good at and enjoying.

So there won't be more Serial Apeist?!

[Laughs.] Not at the moment.

The Big Bang Theory returns for season nine on Monday, Sept. 21 at 8 p.m. Stay tuned to The Live Feed for more scoop on Sheldon and Amy as well as the rest of the gang.