Emily Blunt dislikes movies where characters start "tearing their clothes off" too soon.

The British actress enjoys starring in romantic films but she won't take just any script she's offered. Emily thinks too many big screen love stories are unbelievable, which puts people off.

"I appreciate a slow-burn romance. In most movies, everyone is just tearing their clothes off in the first scene," she told Chicago Sun-Times. "Let that chemistry burn!"

Emily appears alongside Ewan McGregor in Salmon Fishing in the Yemen, about a woman who tries to convince a fishing expert to bring the practice to the desert.

The two stars' characters are romantically interested in each other and Ewan and Emily had to shoot a love scene. It wasn't as sexy as it seems on the cinema screen.

"Oh my God, it was awful," Emily laughed. "The scene called for a midnight swim on our Morocco set. What everyone forgot is that in the desert at night, the temperature plummets. It was supposed to be a romantic and peaceful swim, but our teeth were chattering, plus the water was only about two feet deep. We were scraping our knickers on the rocks below."

Emily has a film called The Five-Year Engagement coming out later this year, which she appears in alongside Jason Segel.

In real life the 29-year-old star is happily wed to The Office actor John Krasinski. She has strong ideas about marriage, and about being with the right person.

"It's all about who is doing the delaying and the self-fulfilment within the couple that keeps shifting. You see the dynamics of this couple over several years. A lot of people have come out of early screenings and told me, It's true to life,'" she said. "Personally, I'm an advocate for short engagements. Long sometimes means there is a reason for it. Two years engaged and no wedding I'd be upset."