'How I Met Your Mother' Co-Creator on Season Finale Reveal

How I Met Your Mother Something New Milioti - H 2013

How I Met Your Mother Something New Milioti - H 2013

Monday's How I Met Your Mother season finale left many viewers frantically googling when the last scene revealed the long-eluded-to mother to be a relative unknown.

Actress Cristin Milioti, a Tony nominee for her starring role in Once, is the Girl With the Yellow Umbrella -- a role that will figure prominently in the ninth and final season when Ted (Josh Radnor) finally meets the wife he's been having near misses with since the CBS comedy began in 2005. 

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“It was a pretty big umbrella to fill, casting the title role in a series that's been on the air for eight years,” said co-creator and executive producer Carter Bays in a Tuesday note from the network. “And yet Cristin Milioti is, against all odds, exactly what we were looking for. She made us laugh on 30 Rock, she made us swoon in Once, and her ukulele skills are no joke. We're thrilled to welcome her to the How I Met Your Mother family, and look forward to getting to know her -- and the character she plays -- much better in the coming final season."

Not much was seen of the Mother, save a few telling glimpses of her previously seen boots and yellow umbrella. Milioti wrapped the episode buying a train ticket to from Manhattan to Farhampton, where previous episodes have revealed she'll play in the band and Robin (Cobie Smulders) and Barney's (Neil Patrick Harris) wedding and ultimately meet Ted on the train platform.

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To keep the casting from leaking, Milioti's scene was filmed in secret on Los Angeles' Twentieth Century Fox lot on March 27. Many previous mother-related scenes have been shot on closed sets, as was one yet-to-be-used flash forward featuring the future Mosby children played by Lyndsy Fonseca and David Henrie. (The pair have been seen several times since the start of the series, listening to their father's narration.)

"To all the fans, on behalf of all of us writers, cast and crew: Thank you for sticking with us on this wild journey," added Bays. "Our ninth season will tell the epic story of the longest wedding weekend ever. We hope you like it. Next stop, Farhampton.”

Email: Michael.OConnell@THR.com; Twitter: @MikeyLikesTV