If there was a movie equivalent of David and Goliath it could be summed up by the box office chances of British actor JJ Feild’s latest films.

Goliath would be Captain America, a £140 million all-action, effect-laden, comic book adaptation due for release in July. David would be Third Star, shot on location in Pembrokeshire with an ensemble cast of four for just £400,000.

Feild, who joined co-stars Benedict Cumberbatch, Tom Burke and Adam Robertson to make the low-key film, is well aware of the gulf between the two movies.

“I literally just finished Captain America a couple of weeks ago,” he says, from the countryside retreat of his parents.

“I play one of the Captain’s sidekicks, so I’ve been running around, shooting guns, blowing things up and trying to look cool for about a year,” he laughs. “I’m looking forward to relaxing and finding some nice dialogue to speak.”

Third Star, on the other hand, which was shot in just one month in September 2009, is described by Feild as “a labour of love”.

He explains: “It’s a beautiful film and it’s very rare that actors get to do work we’re deeply proud of. I hope it ends up being enjoyed by people because we had a beautiful time making it.”

Cumberbatch, best known for his recent turn as a modern-day Sherlock Holmes, plays James, a young 20-something with a terminal illness, who asks his three best friends to join him on a camping trip to his favourite place, Barafundle Bay in Wales.

Feild, 33, who possesses such graceful airs, good looks and talent that he could be Jude Law’s younger brother, was born in America but moved to the UK shortly afterwards.

He first read the script of Third Star five years ago and is grateful the project has finally come to fruition.

“It was very hard to get it made and I don’t understand why. We kept getting told it wasn’t topical enough or British enough. But it’s about an Englishman, a Scotsman, a Welshman, practically the entire funny joke, going on a road trip across the British countryside. It’s also about one of the most talked about subjects in the media, which is care for the dying.

“It’s one of the most relevant films in any cinema at any time and I hope that people will go and see it.”

Feild, whose credits include Northanger Abbey, Telstar and Centurion, plays the arrogant Miles, who undergoes the biggest transformation as he tries to come to terms with what James is going through.

“He starts off a very angry and bitter, confused and frightened man and he has to let all of that go. I think that’s the journey everybody goes through at some point in their lives.

“It’s a dream to get a part where you have something to overcome. At the beginning, he hides behind cruel humour and goes from someone who’s constantly blaming people, to taking responsibility on his shoulders and learning about himself.”

While Captain America may have afforded Feild all the luxuries of a big-budget blockbuster, there was no such treatment on the set of Third Star. While the characters turn in four to a tent each night, the actors bunked up together in a cottage and shared bathrooms to save costs.

“It was as good as camping,” says Feild. “We did everything ourselves. When you’re shooting a film in limited time, you’ve just got to go out there and do it.”

He admits that although there was plenty of camaraderie between the four actors, they couldn’t help but be affected by the subject matter - and tears were shed on the stunning Pembrokeshire set.

“Everybody knows someone who has had cancer, or has died of cancer, and maybe people know someone who was too young to have died. But it’s not a depressing film, it’s a beautifully uplifting human film.

“We’re not meant to say it’s a comedy,” he adds, with a laugh, “but it is very funny and cancer is involved. It’s really about friendship.

“People were blown away by it and there were tears at random times from people making something they believed in.”

One of the hardest days of filming came when Miles had to carry James, after the cart they pushed him in failed.

“I tried to look like I was being all strong and butch, but humans are really heavy,” says Feild. “Luckily Benedict lost loads of weight for the part so it wasn’t too bad, but carrying an actor for too long can’t be right for the psyche.

“One day, we spent all day shooting the scene when I first pick him up and then there was a technical difficulty. We had to come back a week later and do it all over again, so we got to do it twice.”

Come July, there’ll be all sorts of buzz around Feild and his British co-stars in Captain America, Hayley Atwell and Dominic Cooper, but for now he’s enjoying a break and looking forward to his next project, whatever it may be.

“I’ll never try and do the same job twice, that’s the hope and the prayer.”