Anne Hathaway was proud to keep her butt in "great shape" when she was pregnant - only to later realise she'd caught a glimpse of her stunt double's derriere.
The 34-year-old actress - who has 12-month-old son Jonathan with husband Anne Hathaway - was adjusting to her changing figure while shooting 'Colassal' with Jason Sudeikis and couldn't recognise herself on screen.
She admitted to Vulture: "It's funny because your body changes when you're pregnant. And it was my first pregnancy so I didn't know what was going on.
"There's a shot in the movie when I saw it and I was like 'oh see, I kept my butt in great shape'. And the second time I watched the movie I realised it was her [the stunt double]."
Anne donned a wig for her role as party girl Gloria in the movie, and she admitted that in her pregnant state, she couldn't bear having to wear the headpiece for long.
Asked about the wig, she said: "I think, 'Just get it off me.' I was pregnant. I just wanted that s**t off."
In 'Colossal', Gloria moves back to her small hometown where she meets her old classmate Oscar. The film then moves into a story about alcoholism and control and the brunette beauty enjoys the way the viewer's perceptions of the characters change as the plot shifts.
She said: "One of the things I love about this movie is the way the exact same circumstances feel different as the movie goes on.
"We do tend to sum people up and we tend to decide who other people are rather than actually listening to what they're telling you.
"This movie plays with those ideas. Part of the reason why Jason's performance is so effective is because you think you know him from the beginning."