London: Katherine Heigl, whose movie `Killers` recently premiered in London, says acting in the action-comedy flick was "painstaking".
"It`s really fun but it`s little bits at a time, so it`s a little bit painstaking for me. I like those dialogue scenes where you`re sort of bantering," a news daily quoted Katherine, as saying.
The former Grey`s Anatomy actress added: "One of my favourite scenes of the movie was the pregnancy test scene because that was just sort of Ashton and I improv-ing. I thought that we were really good at bickering together!
"The action side of it that requires everything being re-set and put in its place ... so it can take a day or two to do one tiny little thing."
Katherine is paired opposite Ashton Kutcher in Killers.
The film hits cinemas on June 18.