AceShowbiz -

Meg Ryan joins "How I Met Your Mother" spin-off, "How I Met Your Dad". The "When Harry Met Sally..." star, however, will not appear on-screen since she's cast to voice the mother in the CBS comedy pilot.

The actress will narrate the show as she tells the kids the story of how she met their father. "Full House" alum Bob Saget landed the same role on the original show, supplying the voice of future Ted who told his children how he'd met the titular mother.

"How I Met Your Dad", which has yet to receive a series order, was scheduled to film its pilot in Los Angeles but will move to New York if it is picked up to series. "HIMYM" creators Carter Bays and Craig Thomas and "Up All Night" creator Emily Spivey shepherd the project.

Greta Gerwig lands the lead role as Sally who is described as a "vibrant, messy and unpredictable" woman in her twenties and as a "female Peter Pan who has never grown up and has no idea of where she's going in life."

She's thinking of calling it quits with her husband of a year, Gavin, who will be portrayed by Anders Holm. Krysta Rodriguez and Drew Tarver are cast as Sally's friends, while Andrew Santino will play her older gay brother.

The pilot is expected to include a reference to "HIMYM" as it will feature Ted and the gang's favorite hangout, MacLaren's Pub. "It's funny. It shares the heart and soul with the original show, so it has the sweetness and the funniness," Gerwig, who will also produce the comedy pilot, recently told E! News.

Ryan's last feature film role was in 2009's "Serious Moonlight". She has guest starred in several episodes of Lisa Kudrow's "Web Therapy", which was initially launched as a web series and later brought onto Showtime.