"How I Met Your Dad," the upcoming spin-off from the successful CBS series "How I Met Your Mother," will star Greta Gerwig and while some "How I Met Your Mother" fans may be skeptical of a spin-off, Gerwig assures viewers that she is just as much a "HIMYM" fan as they are.

"I've been a fan of ["How I Met Your Mother"] since really early on. I've seen every episode. ["How I Met Your Dad"] is funny. It shares the heart and soul with the original show, so it has the sweetness and the funniness," Greta Gerwig told E! News.

The star of "Frances Ha" also added that the "How I Met Your Mother" cast have been very supportive of her new gig.

"They're so nice. I went and I hung out with all the cast and they were like, 'If you can be part of this world, it's crazy fun.' They told me they believed in me, and it was really sweet," she said.

"HIMYD" is a joint creation from "How I Met Your Mother" creators Carter Bays and Craig Thomas and "Up All Night" creator Emily Spivey.

Gerwig will play Sally, "a sweet yet free-spirited girl in her late-20s who has never really embraced the notion of growing up. However, unlike Ted (Josh Radnor), Sally is already married when we first meet her in the pilot," E! News reports.

Gerwig will also serve as a writer and executive producer alongside Bays and Thomas in "How I Met Your Dad."

"I contributed a lot into the pilot, and I'll be in the writers room staring June 1 if they pick it up," she said. "I shoot the pilot in like two weeks and then hopefully it becomes a real show."

Meanwhile, "HIMYM" is in it's final season, with just a few episodes left before the finale. Catch "How I Met Your Mother" season 9 Monday nights at 8/7c on CBS.