Making a movie about forbidden first love when you're fresh from the most soul-crushing public breakup of your life doesn't exactly sound fun.

Actually, it sounds like literal hell.

But Kristen Stewart, who had to do exactly that when she joined the cast of "Equals" in the aftermath of her high-profile 2014 split with Robert Pattinson, was comforted by the fact that at least she wasn't alone: Her co-star, Nicholas Hoult, was going through the exact same thing.

In an interview with The Daily Beast, the actress revealed that she was still reeling from the breakup when she first showed up on set.

"It was incredibly painful,” she said. “Ugh, f--king kill me."

But the pain was something she had in common with Hoult, who was fresh from a similarly public split with Jennifer Lawrence -- and being able to work through it on set ended up being the best thing, for both of them.

"It was a really good time for both of us to make this movie. Not all of my friends have been through what I’ve been through, or what some people have tasted at a relatively-speaking young age, and we were not expected to do anything," Stewart said. "Everything that we did was explorative, and a meditation on what we already knew."

Not that it was easy to confront those feelings while they were still so fresh, she said: “And to acknowledge it, reassess, and jump back into it? Usually you want to move on. But at least we could use some of that for some good. This movie was a meditation on firsts, and a meditation on maintaining, and a meditation on the ebbs and flows of what it’s like to love someone -- your feelings versus your ideals, the bursting of bubbles, the shattering of dreams you thought were possible, and what you have to contend with as things get more realistic.”

In short: Heavy stuff. But one year later, Kristen seems to have a clearer perspective on things -- and a lot more comfort with ambiguity. Her takeaway from all that meditation on heartbreak?

“Relationships,” she said, “you just never f--king know."