Keira Knightley choked back tears when recalling the horror she witnessed on a recent charity trip to refugee camps in South Sudan.

The Pirates of the Caribbean actress visited the victims of the region's civil war to coincide with the three-year anniversary of its independence from Sudan, which will be celebrated on Wednesday (09Jul14).

However, she became emotional when discussing the Oxfam trip in a recent interview, telling Britain's Daily Telegraph newspaper, "I didn't cry when I was there. What b**ody right would I have to cry when the people I met, who were living in as near to hell as I can imagine, weren't crying?

"I'd never been to a refugee camp before, but I'd seen images. I read newspapers, so I know what goes on in the world, don't I? But I'd never been to a post-conflict zone, I'd never experienced the incredible, palpable atmosphere of terror..."

Despite her humanitarian visit, Knightley has no plans to follow in the footsteps of Angelina Jolie, who was made an honorary Dame by Britain's Queen Elizabeth Ii in June (14) for her charity work.

Knightley adds, "I don't think I could be ever be anything like as impressive or authoritative as she is on the world stage. She's pretty much devoting her life to her causes, and that's a great thing, a great message. I'm always happy to help any small way I can."