Logan Lerman and Sarah Gadon were very relaxed when it came to filming sex scenes for movie Indignation.

The Perks of Being a Wallflower actor stars as Marcus, a Jewish college student who experiences his sexual awakening following a date with Sarah's character Olivia in the 1950s-set coming-of-age tale.

Olivia performs a number of sexual acts with Marcus, and director James Schamus was concerned about ensuring the actors were comfortable during the scenes. Though it seems he didn’t need to be so worried, as the pair took them in their stride.

"If you ask Logan and Sarah, I think they found it very funny that I was concerned for them because they were like, 'Eh, this is our job! That's what we do,'" James joked to WENN.

He added that those scenes are very technical to shoot and the crew were so focused on getting everything right that it overtook any feelings of awkwardness.

"The pure physical production really takes over so everybody has a cushion which is, 'We've just got our job to do. We have a job to do here'. I think that helps everybody get through it," he explained.

James also joked that he had the "great luxury" of having a low budget because it meant he had the freedom to cast whoever he felt was right rather than having to pick "big" names.

He met Logan in Los Angeles for a quick chat about the part but they ended up talking for four hours and he knew he'd found his Marcus. James chose not to do a chemistry test between Logan and Sarah because he had "full faith" in their acting ability.

Indignation premiered to rave reviews at the Sundance Film Festival in January (16) and is released in U.K. cinemas on Friday (18Nov16).