By Sandra Gonzalez
Updated March 16, 2014 at 01:53 PM EDT
Frazer Harrison/Getty Images

The secrets of How I Met Your Mother‘s impending series finale stayed under wraps as ever during the latest stop on the cast and creative team’s Farewell Tour on Saturday night. But what did we learn at the PaleyFest screening and Q&A at the Dolby Theater in Los Angeles? Here are some of the highlights…including a detailed account of Neil Patrick Harris’ shirtless moment via webcam:

This week’s episode, titled “Gary Blauman,” wraps up many supporting characters’ storylines in a very unique way and also features yet another can’t-miss milestone moment between Ted and The Mother.

There will be a final slap. While executive producer Craig Thomas declined to give specifics, he assured, “We didn’t forget.” As for the series finale itself, both Thomas and fellow co-creator Carter Bays were understandably tightlipped when confronted by the “Is the mother dead?” question, with Bays saying, “We’re wildly excited about the finale…but we can’t say anything.”

Alyson Hannigan once auditioned for a role on Blossom and was told she wasn’t funny enough. She also shared that she “couldn’t get a Saved By the Bell callback to save my life.” It obviously worked out for the Buffy the Vampire Slayer alum in the end, but when prompted for acting advice by a young fan in the crowd, Hannigan said, ” It’s really hard, but if you love it, it’s totally worth it. But I hope you have a good therapist.”

“La Vie en Rose” holds a special meaning to Bays. The executive producer revealed that the tune, which was memorably sung by Mother Cristin Milioti in the 200th episode, is a song that he often sings to his children before bed, accompanied by a ukulele that he bought in Hawaii while there for his wedding. Meanwhile, Milioti said the song has also been a favorite of her family for a long time, and to surprise them, she told no one that she was going to sing it on the show.

Barney and Robin will exchange vows. Yes, we’ve seen the couple’s wedding pictures and the whole season has been set at their wedding, but it’d be a lie to say we weren’t a little relieved when Neil Patrick Harris, who Skyped in — sans shirt! — for a portion of the event from New York (where he’s performing in Hedwig and the Angry Inch), said one of his highlights of the final season was “getting to say my vows.” Now we know they at least make it that far! Meanwhile, our highlight of the night? NPH’s Skype farewell to his castmates and the producers, in which he called Hannigan the “heart of the show” and told Cobie Smulders that there’s “no girl in my life I’d rather marry.” (The moment got huge laughs.)

Watch Neil Patrick Harris go shirtless at the panel below: