The Marvel Cinematic Universe is constantly growing. 2014's "Guardians of the Galaxy" introduced audiences to the cosmic side of the MCU, and this November "Doctor Strange" will show them what it's like when Marvel goes supernatural. And it looks like those two add-ons to the comparatively grounded Marvel U might just meet up in "Doctor Strange" as well, according to an interesting tidbit dropped by Tilda Swinton in an appearance on "Jimmy Kimmel Live."

Swinton, who plays the Ancient One in the film, told a story about how her kids got to do work placement on the Marvel movie for school credit. Even some of their classmates got to join in, working on the stunt team. Swinton's teens, who were initially reluctant to get involved with their mom's movie, also made an impact on the film.

"My son was with the art department and my daughter was with the costume department," said Swinton. "And they loved it." Her daughter worked to "break down" the costumes, taking the garments worn in the movie and covering them with mud and dirt. Her son's work will also be seen onscreen.

"We had this amazing moment one day when I met him for lunch in the canteen and I said, 'What did you do this morning?' He said, 'Made a planet,'" said Swinton of her surprise conversation with her son. "And it's a planet -- I've now seen the movie and I can tell you it appears to great effect at the end of the movie." Host Jimmy Kimmel also confirmed this.

This just fuels further speculation as to how "Doctor Strange" will interact with the larger MCU. There's already a set photo that hints at a Strange encounter in "Thor: Ragnarok," and "Thor" director Taika Waititi hasn't really confirmed or denied it. And of course it's well-known that "Ragnarok" will take place on other planets and be a part of Marvel's cosmic universe.

You can watch the interview clip here -- and it's also worth it for the surprise Swinton gives two audience members towards the end of the interview.

Directed by Scott Derrickson and starring Benedict Cumberbatch, Rachel McAdams, Tilda Swinton, Chiwetel Ejiofor, Mads Mikkelsen, Benedict Wong and more, “Doctor Strange” arrives in theaters on November 4.