*possible spoilers ahead*

Sure, there’s a death investigation for viewers to follow along with, but the biggest mystery in “Knives Out” actually ends up being, “Is ‘Deadly by Surprise’ a real Hallmark movie with Danica McKellar?”

That’s right, it’s time for Hallmarkies to welcome Rian Johnson to the Hallmark fan club because the “Knives Out” writer and director includes not one but two mentions of Hallmark and one of the network’s biggest stars, McKellar, in his new mystery movie. And McKellar, herself, had some thoughts on it.

Starring Daniel Craig, Ana de Armas, Jamie Lee Curtis, Chris Evans and many others, the flick, which is now out in theaters, centers on “when renowned crime novelist Harlan Thrombey (Christopher Plummer) is found dead at his estate just after his 85th birthday, the inquisitive and debonair Detective Benoit Blanc (Craig) is mysteriously enlisted to investigate,” according to Lionsgate. “From Harlan’s dysfunctional family to his devoted staff, Blanc sifts through a web of red herrings and self-serving lies to uncover the truth behind Harlan’s untimely death.”

The first mention of Hallmark arrives about halfway through the movie. While everyone’s gathered inside the Thrombey home mourning the death of Harlan, one of the estate’s helping hands, Fran (Edi Patterson), tells the late novelist’s nurse, Marta (Ana de Armas), “I don’t think he killed himself…There’s this Hallmark movie, called ‘Deadly by Surprise,’ with Danica McKellar, and she plays this wife who’s getting poisoned by her husband.”

Fran goes on to explain that the husband poisoned McKellar’s character a little bit at a time so she didn’t know it was happening, but she felt something was off and ended up killing herself. Apparently, Fran’s cousin does secretarial work at the Medical Examiner's office, and “she says that stuff totally happens.”

For those wondering, McKellar does have her own Hallmark Movies & Mysteries series, and the first movie, “Matchmaker Mysteries: A Killer Engagement,” debuted last month, but “Deadly by Surprise” is not actually a real movie. That said, HM&M films often have a lot of deaths and poisoning, so it could be in the future.

Clearly, the characters within “Knives Out” love the concept of it because everything comes full circle when the network and the actress are mentioned again near the end of the movie, with Marta now saying, “Oh God, that Hallmark movie [Fran] told be about with Danica McKellar…That’s what she was talking about.”

To find out the whole context of the Hallmark reference, fans will have to check out “Knives Out” in theaters, but when International Business Times at Christmas Con 2019 earlier this month gave the network star herself, McKellar, a little tease of the movie mention, she was delighted.

“Haha, that’s awesome,” she told IBT. “I’ve got to go check this out. I just found out about it right now, and I’m incredibly honored and flattered. That’s really sweet.”

She was so pleased about this, in fact, that she did end up going out to watch the movie to see and hear it all for herself.

McKellar shared on Twitter on Wednesday that she saw the movie and wanted to send a “Huge thank-you to the writer/director @rianjohnson for not only making a truly entertaining whodunnit, but also for including me in its lore.”

“Knives Out” is now out in theaters. McKellar’s new Hallmark movie, a holiday flick not a mystery, called “Christmas at Dollywood,” premieres on Hallmark Channel on Dec. 8 at 8 p.m.