Emily Blunt has revealed the challenges of acting in front of a green screen.
The British star found out how difficult it is to act with CGI (computer generated imagery) on Gulliver's Travels, in which she stars opposite Jack Black and Jason Segel.
"[It is] hell, I find it really tedious and confusing - you're like begging a tennis ball on a pole for help and crying!" she told Access Hollywood.
"I think that's [the moment] when you're like, 'Oh wow. This takes a lot of imagination!'," she added.
While the green screen may have been a nightmare for Emily, working with her co-stars was completely the opposite.
"Heaven - they're so much fun," she continued.
"I mean, they're too much fun! It almost ruins you for other actors, you know? They're really delightful and sweet, and it was just like a comedy fest on that set."
:: Gulliver's Travels opens in cinemas on Boxing Day (December 26).