19 surprising things you probably didn't know about 'How I Met Your Mother'

"How I Met Your Dad" was in the works after the "HIMYM" series finale, but it was ultimately scrapped in 2014 due to creative differences between the writers and CBS, according to Deadline. The unaired pilot starred Greta Gerwig as Sally, a recent divorcée on the hunt for new love.

In 2017, Deadline also reported that a similar spin-off called "How I Met Your Father" was moving forward, but the show still hasn't been confirmed.

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According to CBS News, the final scene of Ted's kids learning that Ted still loved Robin was filmed in 2006 to ensure the actors playing the kids still looked the same.

That was only a year after the show premiered and eight years before the finale aired.

David Henrie and Lyndsy Fonseca, who played the kids, had to sign non-disclosure agreements, and only one camera operator was allowed in the room while they filmed the final scene.

According to E! News, Bays told Reddit that a season-one cancellation would have resulted in them writing Victoria in as the mother.

Of course, the show actually went on for nine seasons, so that plan got scrapped.

According to The Obsessive Viewer, the official "HIMYM" Facebook page posted a photo of the mother right after the episode that revealed her identity aired.

However, not every fan was able to watch the episode live, so they had the series-long plot point spoiled for them if they scrolled past the post.

Bays told TV Squad that his assistant, Carl McLaren, lent his name to the bar, McLaren's, and to its bartender, Carl.

Her Campus reported that most of the websites the characters shout out on the series are actually live on the internet.

See for yourself at tedmosbyisajerk.com, barneysvideoresume.com, and notafathersday.com to name a few.

You can buy the series-approved version of all of Barney's rules, and it's even "written" by Barney Stinson himself.

According to Entertainment Weekly, the actor has even written a children's book about magic, so it's clear that Harris influenced Barney's hobby.

When Lily did end up having a child on the show, Hannigan's young daughter was set to play the role.

But, Hannigan told the HuffPost in 2017 that they decided she was too old for the part.

"They fired my kid from that role. She was gonna be the baby, but Carter Bays was like, 'Nope. She's too old,' and she got replaced," Hannigan said.

During season five, the actor who played Robin and the actor who played Lily were both pregnant, but their characters were not. So the props team just kept hiding their growing bellies behind large props and handbags.

"We have the biggest purses of any show on the air," director Pamela Fryman told the Chicago Tribune.

Lily's high-school sweetheart Scooter was portrayed by Harris' husband David Burtka.

Alyson Hannigan, who played Lily, also shared the screen with her husband, Alexis Denisof, who had a recurring role on the show as Robin's coanchor Sandy Rivers.

Smulders' husband Taran Killam was another spouse who made it onto "HIMYM." He actually played two characters on the show, a one-time appearance as Derrick and the recurring character Gary Blauman.

In 2018, Harris agreed with a popular fan theory in an interview with Digital Spy.

The theory speculated that Ted made Barney sound extra sleazy and womanizing in his story for his kids because he didn't want them to judge him for falling for Barney's ex-wife, Robin.

"I think that that's very accurate," Harris told Digital Spy. "Given the story structure, and with [Ted] telling the story to his kids, everything was able to be overdrawn."

Smulders was apprehensive when there were initial chats about the characters getting together, but Harris actively tried to make it happen throughout filming.

"I'd try to do little things in our scenes together where I gave her an extra look and an extra glance or would stare only at her during a whole scene just to see if anyone was noticing," Harris told The Fan Carpet of his own personal mission to get Barney and Robin together.

According to the New York Daily News, Jana Rugan and Timothy Russo really got engaged on the season-two finale.

Russo's friend wrote for the series and arranged for the couple to stand in as extras since it was Rugan's favorite show.

On the episode, Robin and Ted were on a date when the waiter mistakenly brought Robin a champagne glass with a ring at the bottom. She freaked out — and so did Ted since he wasn't actually proposing — then Russo came over to claim the ring as his and proposed to Rugan for real.

"At first she thought I was messing up the scene, then it dawned on her and she started crying and everyone was clapping. It was awesome," Russo told the Daily News.

The pop singer guest-starred as Abby the receptionist on season three, episode 13. According to E! News, cocreator Carter Bays told Reddit that she helped bring in new viewers and saved the show from low ratings.

"By golly she put our show on the map. It can't be overstated," Bays wrote. "Britney Spears rescued us from ever being on the [renewal] bubble again. Thanks Britney!"

Real-life Canadian Cobie Smulders eventually snagged the part of Robin, but only after Jennifer Love Hewitt turned it down.

According to E! News, cocreator Craig Thomas wrote on Reddit that Love Hewitt decided to do CBS' "The Ghost Whisperer" instead of "HIMYM."

Before Neil Patrick Harris landed the role, Jim Parsons auditioned for the show. But there are no hard feelings from the "The Big Bang Theory" star.

"Look, it all worked out fine … Neil's better for the part, let's be honest," Parsons said on a 2015 episode of "Live With Kelly," according to Yahoo.

New York City may be a central character in the series, but according to the New York Post, they really filmed on a studio lot in Los Angeles that was designed to look like the Big Apple.

Josh Radnor played Ted on the show, but Bob Saget was cast to do the "future Ted" voice-overs that narrated the series.