“How I Met Your Father” started with a bang with Sophie (Hilary Duff) describing the lowest point in her life — “I think I’m dating my father” she frantically tells her mother (played by Paget Brewster) over the phone.

But fans of the show are nowhere near finding out who is Sophie’s father than they are finding the eponymous father – the love of Sophie’s life.

Speaking to ET Canada about the show’s best-kept secret, Duff, the protagonist and one of the producers, said, “Since I’m a producer, I do get episodes like before everybody else — which is so braggy and awful. But like the way that they protect them, you would think that I was dealing with Marvel footage like the pics and like double step authenticator. I just end up not watching them because I can’t get to them. It’s very, very like them. I don’t know who the father is and to be honest with you, I don’t think our creators know.”

A still from ‘How I Met Your Father’
A still from ‘How I Met Your Father’ — Photo by: Patrick Wymore/Hulu

“Yeah, I think that they’re like they have really good mapped out vision of like the seasons. But I don’t think that they are boxing themselves into any one person,” she added.

Viewers were in for another surprise as another “How I Met Your Mother” alum was introduced. The showrunners teased Neil Patrick Harris’ cameo at the end of the first episode. “I know when I was working with Neil, I was definitely nervous. And he’s just so great and charismatic and. He’s very easy on him,” Duff said.

Neil Patrick Harris and Hilary Duff in a scene from ‘How I Met Your Father’.
Neil Patrick Harris and Hilary Duff in a scene from ‘How I Met Your Father’. — Photo by: Patrick Wymore/Hulu

Last season, fans saw Cobie Smulders (Robin Scherbatsky) appearing on the show to give Sophie advice. Fans have also met George Van Smoot or The Captain (played by Kyle MacLachlan) and Becky (Laura Bell Bundy) from “How I Met Your Mother” and they’ve played a crucial role in steering Sophie’s relationship with Daniel Augustin.

“I think that we all really appreciate what they did. You know, they spent nine or ten years on that show creating some serious TV magic,” Duff said of returning members. “We all really stand by the fact that our show is very different than that. But they really created a format for us to have this. And the fact that they’re willing to come on our show… I think we all feel a little star struck,” she added.

 

“The way that our creators are tying in their visits to us, it’s just unique. And I could never dream up how they do it. So, we’re having lots of fun and we hope to excite the audience by bringing them all.”