PaleyFest attendants said goodbye to How I Met Your Mother in legendary fashion Saturday night as actors and show runners from CBS’ hit comedy series took the stage for a very special farewell panel. Hypable was in attendance as actors Josh Radnor, Cobie Smulders, Alyson Hannigan, and Cristin Milioti, took the stage at the Dolby Theater in Hollywood along with producers Craig Thomas, Carter Bays and executive producer Pamela Fryman to talk slap bets, favorite moments, the series finale and more.

Here are five legendary things we learned from the How I Met Your Mother farewell panel at PaleyFest:

This Monday’s episode will feature more than a few familiar faces

Fans lucky enough to attend the How I Met Your Mother panel at PaleyFest were also lucky enough to get an early screening of season 9, episode 21 before it airs this Monday at 8 p.m. on CBS. While we don’t want to spoil it for all you readers out there who would rather experience it first hand, we will say this: The episode, which is called “Gary Blauman,” brings back more than a few familiar faces from Ted’s past.

Marshall will get a final slap in!

“We didn’t forget!” said executive producer, Craig Thomas, when a pair of seemingly suited-up fans sitting up in the balcony at the Dolby Theater asked if there would be a final slap before the season ended. Sadly, Bays and Thomas are both keeping tight lipped on how exactly Marshall delivers the final slap to Barney but rest assured, HIMYM fans, the infamous slap bet will not go unfulfilled!

Is the Mother dying?

Shortly after cast and creators took the stage, moderator and frequent HIMYM guest star, Wayne Brady didn’t waste much time before addressing the latest rumor currently making rounds on the internet. “Would you really kill off the mother?” Brady asked, stating that America really wants to know. Naturally, the show runners are keeping very tight lipped on everything regarding the series finale. “We’re wildly excited about the finale,” said Bays, effectively dodging the question. “I wish we could tell you what’s going to happen.”

Show runner Craig Thomas dished on the last scene they ever shot…

And fittingly, it was the scene where Ted finally meets the Mother for the first time. Thomas reminisced on the fateful moment in the series where Ted finally meets the yellow umbrella carrying mother saying there was a “gleeful feeling” to finally getting to that point. “We waited so many years for Cristin to show up — imagine if we’d cast that wrong. We would have had to issue an apology and go off air!” joked Thomas. Finally, in a humble moment, the producer added, “We got to wait nine f–king years before we met the mother — it took nine f–king years and somehow you all watched! Thank you so much.”

Neil Patrick Harris skyped into the panel from NYC and it was legen–waitforit–DARY

Despite being a bit tied up with rehearsals for Hedwig and the Angry Itch, Neil Patrick Harris took a few minutes out of his busy schedule to skype into the panel. While Harris stayed away from revealing any juicy details regarding the last three episodes in the series, he did say that the thing he loved most about playing Barney was watching him evolve into the man he becomes when he falls in love with Robin. Things got a little emotional when Harris began to wax poetic on his fellow cast members, calling Hannigan and Radnor the “heart” and “soul” of the show, respectively. Finally, in a moment that drew enormous laughter from the crowd, Harris addressed his on-screen love interest Cobie Smulders saying, “There is no girl in my life I’d rather marry.”

Have a favorite moment from last night’s How I Met Your Mother panel at PaleyFest? Share it with us below!