At the end of last season we finally did it.  We met the mother.  It was a moment eight seasons in the making, and delightful as it was, fans are still waiting to see the titular moment when Ted Mosby meets the future mother of his children.  In honor of their ninth and final season the cast of How I Met Your Mother made their Comic-con debut to a packed house of fans and bring them a glimpse of what to expect from the show’s conclusive season.

Following the panel Executive Producers Craig Thomas and Carter Bays spoke with the press. They talked about seeing the kids again after so many years, getting the opportunity to finish the show properly, casting the mother, their favorite moments from season eight, and more. Check out what they had to say after the jump.

Can you talk a little bit about that video you just showed with the kids?

CRAIG THOMAS: We hadn’t seen Lindsay and David in years and years and years, and one of the funny things is, they walked in and they don’t look that different actually! They don’t look quite as different as we wanted them to.

CARTER BAYS: Luckiest kids in show business.  We’ve been sending them paychecks for eight years.

THOMAS: That was a good gig.  We hadn’t seen them in years and they came in, and we hadn’t even talked to them about what the script was, and it’s dirty, and so they came in and we’re like, “You’re cool with this?” And they were like, “Fuck yeah.”  They were totally into it and they love the idea of subverting – I mean, they’ve been frozen as children on television for eight years.  They can’t age and they can’t leave that couch, so getting to come back in and play with that, subvert it was really fun for them.

BAYS: And this whole season for us is largely about the way that it is at weddings, it’s about seeing all these people that we haven’t seen in a million years.  So it was a nice way to start off this season that’s going to be a kind of cavalcade of all these great actors we’ve had a chance to work with.

THOMAS: We shot a little piece of the very end of How I Met your Mother with the kids in season two before they got too old…and we haven’t seen them in years.  It has to do with how the series ends, and the funny thing is we said, “We’re going to get to that piece this year.  We’re ending the series.”  And David Henry was like, “I know, that was amazing.  That’s such a cool piece that we shot.”  And Lyndsy [Fonseca] was like, “I have no memory of shooting that.”  So I was thanking them for keeping it a secret all these years and Lyndsy was like, “I forgot it, so you don’t even have to thank me.”

Has your plan of how the series would end changed a little?

THOMAS: No, the very end has not changed.  We thought we’d be done after eight seasons so season nine is a bonus year.  It’s the Wild West and anything could happen.  We’re changing a lot of the rules of how we thought we were going to tell the story.

BAYS: Yeah, I think the story hasn’t changed, but how we tell it has changed now that we have 24 episodes to expand on it and see a little bit more of it.  It’s nice.  Knowing what we have left to tell, this little story that we’ve been meaning to tell for eight years now, it would have felt really abrupt to end it after eight seasons.  So we feel very lucky.  This is a chance that no one gets in TV.  Usually your series finale is the last one the studio is willing to pay for and then they pull the plug.  It makes us really grateful.  It is kind of like writing a really long book and to be able to write the last chapter the way we want to write it is an opportunity we’ll probably never get again.  It’s really something were very grateful for.

For the season eight DVD, are there any deleted scenes you loved that didn’t make it to the screen that we might see on that DVD?

BAYS: I’ll tell you something that’s not going to be on this DVD, but a future DVD, is when we were casting the mother we flew in Cristin [Milioti] to do a screen test with Josh [Radnor]. Just to know that they had chemistry.  We wrote the scene where they meet, it was crazy to actually be writing those words, putting them on paper, and then to see them actually acted out by these two people.  We really want to show that footage eventually at some point. 

THOMAS: That will be on the year nine DVD, or the series boxset DVD.  We don’t know yet.  It’s really cool.  You see literally the moment that Josh and Cristin met, the moment these two actors met.  They basically said “hi” right then and there and then did this beautiful scene where she has the yellow umbrella.  We almost started crying.

How hard was it to keep the revelation of the mother a secret?

THOMAS: It’s the most we’ve ever tried to keep something secret, obviously.  We shot it on this other stage because our stage is full of the existing sets so we built this big train station set you saw in the season finale and we cleared it.  We didn’t have any extras.  Everyone else you see walking around there are How I Met Your Mother writers, ADs, PAs, which was great.  It was like a family affair.  No strangers or outsiders were part of it.  We just locked it down.  We made everybody that was even there, not that we don’t trust our cast and crew, but we made everybody sign confidentiality agreements.  We were terrified that month and a half between when we shot and aired.  Every day we were terrified that it would get out, but it didn’t and that was great.

Has your vision of the mother changed at all over time or who you cast in the role?

THOMAS: Yeah, I think once you have an actor its different.  You write to their strengths.  I saw Cristin in Once on Broadway, she was amazing in that show, so you learn that person’s strengths.  I think the actor always changes it once it’s cast.  Don’t you think?

BAYS: Yeah, it’s like getting married in real life.  You can picture who the person is you’re going to marry, but you don’t really know until you see that person and then after that moment you couldn’t have imagined anybody else.  That’s kind of been our experience with Cristin.  Craig saw her in Once, I didn’t get to see her, but just her one episode of 30 Rock was hilarious.  It was a fantastic character that holds her own against the cast.  So that felt like we got something very special with Cristin.

Do you have any favorite moments from season eight?

THOMAS: I mean the moment of revealing the mother was one that we pictured shooting for eight years, and Carter and Pam and I were just standing at the monitor shaking.  Just like, “I can’t believe we’re shooting this.”  It’s just something you picture for so long.  It is like picturing your own wedding day or something.  You think about it for years and that was surreal to be thinking about something for so long and finally be doing it.  I can only imagine what the very end of season nine will feel like…way too intense.

BAYS: Barney’s proposal also, that was an amazing episode.  That was really fun to do.

THOMAS: Yeah, “The Final Page, Part 2”, that was one of my favorite episodes last year.

Was it fun messing with the audience a bit with what was going to happen with that proposal?

BAYS: Oh, yeah, that was great fun.  You don’t want to play too many tricks on the audience, but that was – I fell like there was a direct line to the end of season six of Breaking Bad, just the way that there’s something going on that the audience isn’t privy to for a number of episodes and then an amazing reveal.

THOMAS: We came up with the idea – wouldn’t it be great if Barney proposed via his last, greatest, and final play?  We just had the idea of his last play, the last one he’ll ever have run, which kind of made us feel choked up a little bit.  His playbook exists so he can run this one last play to get the girl.  That just made us smile.

BAYS: It felt like a proposal that only Barney could do.

THOMAS: It was a proposal only Barney could do, and yes, it kind of resulted in us screwing with the audience for many episodes in a row, but I hope the payoff was worth it.  I think it was our Christmas episode so its starts snowing as he proposes.  That was probably one of my favorite moments from season eight.