Cistin Milioti [VIDEO]: Who is 'HIMYM's Mother? Carter Bays & Craig Thomas Explain Casting Broadway Actress in Pivotal Role

Season 8 of CBS's hit sitcom How I Met Your Mother aired its season finale last night and finally revealed the role of "The Mother." Though this has concluded the 183-episode question of how it would be, nobody really expected "The Mother" to turn out to be a relatively unknown actress. Who is Cristin Milioti and why was she cast in such a huge role on an incredibly popular sitcom? Luckily, the show's co-creators Carter Bays and Craig Thomas revealed their reasons for casting the 27-year-old actress.

In an interview with Entertainment Weekly, Bay and Thomas took time to answer questions about and explain why they cast the Tony Award-nominated Milioti.

"It was exciting," Carter Bay said about choosing Cristin Milioti to play the mysterious role. "Part of what helped us is our casting director Marisa [Ross], she sort of has been talking about Cristin for two years now. It helped that she turned us onto her and then the more we got to know Cristin and see her work, the more we realized, Yeah, she's the right choice. So that definitely helped, because we didn't want to do a big casting cattle call - we were going to make it 'come audition for Barney's cousin' or something."

Though you may not recognize her, Cristin is an accomplished actress. She was featured in the main role of "Girl" in the Braodway musical Once and even garnered a Tony Awar nomination for her performance. She has also had roles in The Sopranos, Nurse Jackie, and (maybe most memorably) 30 Rock.

According to Bays, the rest of the cast had seen Cristin on stage in Once and her musical background made her a perfect fit for "The Mother" who happens to be a musician.

Bays also talked about the big "train station scene" where we finally get to meet "The Mother." He said that it was kept kind of secretive with the extras in the scene being all crewmembers. Bays said:

"Ultimately, when we were shooting the train station scene - this is actually fun - all the extras are staff from How I Met Your Mother. They're all there. It was really fun. I kind of felt bad for Cristin because it was really like Jesus has risen when she showed up on the set - the whole crew was like 'Here she is, the women we've been waiting for for 10 years!' And she's like, 'I'm just an actor.'"

Here is the closing scene of last night's season finale of How I Met Your Mother where first get to see Cristin: