How do you go from being complete strangers to acting like an old married couple in a matter of hours?
The stars addressed the issue at the PEOPLE / EW / InStyle studio at the Toronto International Film Festival, where Cranston joked, “We went to a day spa and I gave her a mani-pedi.”
For more on the Toronto International Film Festival, go to PEOPLE.com/tiff
RELATED VIDEO: TIFF 2016: Buzzworthy Films
Cranston and Garner play husband and wife in the film, which tells the story of Cranston’s character’s nervous breakdown and subsequent move to their attic.
Check out the clip to learn more about how their spa day, which Cranston describes as a “crash course on intimacy,” helped them both prepare for their roles.