The new star of CBS' How I Met Your Mother revealed in a behind-the-scenes video just how secretive her role as "the mother" really was before the big reveal at the end of season 8.

Cristin Miliotti (The Mother) sat down with co-star Josh Radnor (Ted) and also talked about her role in the show's final season. Miliotti recounts in a video posted on Zap2it how much of a secret she needed to keep her role from everyone not directly involved with the show.

"I couldn't tell anyone. I was under really strict rules to not tell anyone, "she said. "We shot on a separate soundstage because they wanted to keep it a secret, and all of the extras were producers and writers and crew members from the show. So there was like no...it was all intimate."

The short clip also featured some new insights to the character's personality. Miliotti described her as a "lovable nerd" before adding, "She's a little bit of a history nerd; She's a music nerd; She's a literary nerd.

"She's very funny, hopelessly awkward," the actress added. "She's actually kind of a little bit like the female version of Ted."

Radnor also commented on Miliotti's character and just how involved she'll be in the show's final season.

"There was always a question of when would we meet this gal, you know, will it be the last moment of the series and he turns and there she is, or will we never see her? And I thought it was really smart to introduce her at the end of last season, and now it seems like they're threading her through the season," he said.

See Related: 'How I Met Your Mother' Season 9 Spoilers: Titles Revealed & Ted Not Meeting 'Mother' Until Episode 16?

The two began shooting scenes together on Tuesday, including their first kiss. Miliotti said what was initially an intimidating role to take on, it has since turned to one that is exciting and perfect for her.

"It really is a dream come true. That's not a PC term, it's an actual fact," she said.

How I Met Your Mother returns Sep. 23 at 8:00 p.m. on CBS.