NBC and Sony Pictures Television are plotting a spin-off for “The Blacklist” and will air a backdoor pilot this spring, Variety has learned. Famke Janssen has been tapped to star in the possible, female-led series.

Though the network has not made any official commitment to an actual spin-off, should a series be greenlit, it would revolve around Janssen’s central female character, in contrast to the original series, which stars James Spader.

Though plot details are being kept under wraps, Janssen (“X-Men,” “How to Get Away With Murder”) will play a character named Susan “Scottie” Halsted. She will make her debut on the May 5 episode of the flagship series. She will star in the following episode on May 12 — one week before “Blacklist’s” Season 3 finale — which will serve as the backdoor pilot. Insiders tell Variety that Janssen’s character was conceived as Ryan Eggold’s on-screen mother.

Michael Dinner (“Justified,” “Masters of Sex”) will direct the May 12 episode, though a writer has not been determined yet.

The potential spin-off has been in talks since late last year. Speaking to Variety last month, NBC entertainment president Jennifer Salke confirmed discussions were happening, though she stayed mum on further details. “The only thing I can say is where talking about planting some characters in the show, much in the way that we do in the world of the ‘Chicago’ shows. They could be explored as a potential spin-off, but we have in no way committed to a spin-off series,” she said.

“The Blacklist” planted pilot marks the second continuation of a franchise at NBC this TV season, joining “Chicago Law,” which Variety was first to report is in the works at NBC. That project, which comes from Dick Wolf’s super successful “Chicago” franchise, is also in contention for the 2016-17 season, like the female “Blacklist” vehicle, which would give NBC the opportunity to either have year-round “Blacklist” programming or a double-header “Blacklist” block, as the flagship series has already landed an early fourth season renewal.

Though no longer the huge hit it seemed when it aired during season one behind “The Voice,” “The Blacklist” is still a steady performer for NBC, currently ranking as their No. 3-rated scripted program in both adults 18-49 (2.6 rating) and total viewers (10.82 million), according to Nielsen’s “live plus-3” estimates. Having a companion series could fare well for the franchise, as a fresh new show would perhaps bring more eyes to the original, especially through dual promotion on the network.

Janssen is repped by ICM Partners and Brookside Artists.

Update, 5:20 p.m: Should the spinoff be ordered to series, Edi Gathegi will also star as a regular. He currently appears in “The Blacklist,” and would reprise his role of Mr. Solomon. He is also repped by ICM.