Get Ready to Meet the Mother! 5 Things We Learned at 'How I Met Your Mother's' Comic-Con Panel

Fall TV

She may not be a superhero, but fans of "How I Met Your Mother" did wait eight long seasons to learn the secret identity of Ted Mosby's one true love.

And those fans showed up in droves on Saturday to witness "HIMYM's" very first Comic-Con panel, with the entire cast dropping by to tease the CBS sitcom's ninth and final season, debuting September 23 with a one-hour premiere. Here are the five juiciest tidbits we picked up about the final round for the MacLaren's gang.

1. The Mother of all cast additions

Last season's finale revealed that Broadway star Cristin Milioti ("Once") will be filling the role of the yellow-umbrella-clutching Mother. And though it may take a while for her and Ted to finally meet, she'll be a full-fledged cast member next season. In fact, Alyson Hannigan (Lily) said she's already shot scenes with her, and "I have bruises from shooting those scenes." (Hmmm… a hair-pulling catfight, perhaps?)

Creators Carter Bays and Craig Thomas said we'll definitely see The Mother (who's nameless, as of now) interacting with one of the five main cast members in the premiere. And Thomas is thrilled about how well Milioti is fitting in with the tight-knit "HIMYM" cast: "She has chemistry with everyone in the world. Even street signs."

[Related: Everything You Need to Know About 'How I Met Your Mother's' Mother, Cristin Milioti]

2. A season-long wedding, with a twist

We already know that the entirety of Season 9 will take place over the course of Barney and Robin's wedding weekend. But don't expect a "24"-style real time experiment: Bays said, "We don't want to make people think that there's four episodes of flower-arranging." Instead, the season will be full of flashbacks and flash-forwards to fill out the story; as Thomas put it, "it's a flash-forwardier season than ever before."

Some things to look for at the Stinson-Scherbatsky nuptials: exploding glitter cannons, per Bays; a possible Robin Sparkles sighting (Thomas "can neither confirm nor deny, but it's a wedding, and people sing songs at weddings"); and gobs of returning guest stars from seasons past. Who does Neil Patrick Harris (Barney) most want to see come back? Two words: "Brit-Brit." We totally forgot Britney Spears guest starred on "HIMYM"! Not gonna lie: We'd love to see Britney and Barney tear it up on the dance floor together during the reception.

[Photos: The Best 'How I Met Your Mother' Guest Stars]

3. Slapsgiving might be coming early this year

As Barney knows all too well, Marshall still owes him two big fat slaps — and Mr. Suit Up will definitely be feeling the pain this season. As Bays told us in the "HIMYM" press room, "There are two certainties in life: death and slaps." In fact, Bays teased an entire episode this season "that takes place during the course of one slap." Harris also revealed that those slaps really do hurt, you know: "Have you seen the size of Jason Segel's hands? They're like mitts!"

4. Ted's kids are sick of waiting, too

The highlight of the "HIMYM" panel had to be this tongue-in-cheek intro video, with Ted's future kids (played by "Nikita's" Lyndsy Fonseca and David Henrie) complaining about how long it's taking to hear Dad's story about their mother. (We know, right?) Lots of great meta references for fans here — and lots of (bleeped) adult language, too, so brace yourselves:

5. A Westeros/MacLaren's crossover?

Like the rest of us, Bays and Thomas are gigantic "Game of Thrones" fans; Bays confessed in the press room, "I've never fallen off my couch harder than when I watched the Red Wedding." And they found a way to work their "GoT" love into the "HIMYM" season premiere. Barney (always one to root for the villain) will apparently reveal his affection for the detestable King Joffrey. Marshall, please go ahead and slap this guy already, will ya?

The final season of "How I Met Your Mother" premieres Monday, 9/23 at 8 PM on CBS.