Jennifer Lawrence has often had problems with her Mystique costume on the set of the X-Men films, but she was never expecting this.

Speaking on The Graham Norton Show – promoting X-Men: Apocalypse with James McAvoy – Lawrence revealed how her co-stars pranked her while she was peeing.

Watch below:

So, there you go – McAvoy, Michael Fassbender and Nicholas Hoult are quite the pranksters.

“I’ve actually burst into her bathroom with a BB gun while she was trying to pee in a funnel,” McAvoy laughed.

“It’s so hard to do!” Lawrence said in riposte, “because you have to stop while you’re in the middle of peeing to let the rest of it go — it’s a whole scientific process.”

Hilarious stuff. You can tell Lawrence and McAvoy get along very well together. Let’s how they do in Apocalypse, which has been attracting lukewarm reviews thus far.

X-Men: Apocalypse opens May 18.