Keira Knightley was forced to undergo years of therapy following ‘horrific’ Pirates of the Caribbean trauma

Keira Knightley revealed that her time filming Pirates of the Caribbean was 'traumatic' and led to years of therapy.

The actress was just 18-years-old when she first began starring in the fantasy drama opposite Orlando Bloom and Johnny Depp.

Knightley played Elizabeth Swann, the daughter of Governor Weatherby Swann, and the love interest of Will Turner (Bloom).

The first Pirates of the Caribbean film premiered in 2003, led to a further four films featuring the main cast - the latest hitting the screens in 2017.

Now 39-years-old, the actress is one of the industry's most famous faces.

In a 2018 interview with Variety, Knightley opened up about how starring in Pirates of the Caribbean changed her life and landed her in a therapist's office.

She said: "I'm not an extrovert, so I found that level of scrutiny and that level of fame really hard.

"It was an age where you are becoming, you haven’t become, and you need to make mistakes. It’s a very precarious age, particularly for women."

Pirates of the Caribbean catapulted Knightley to global fame (howBizIreland.com/Getty Images)

She then noted the experience was 'traumatic', but had 'set up' her career.

Knightley added: "So looking back, would I do anything different? No, I wouldn't because I'm unbelievably lucky now, and my career is in a place where I really enjoy it, and I have a level of fame that's much less intense.

"I can deal with it now, and that's great. But at the time, it was not so great, and took many years of therapy to figure it out."

The actress feels she learned a fair few lessons as a result of being a young woman thrust into fame.

"We have to be very careful with our young women", she said.

The star admitted she isnt 'an extrovert' (Jeff Spicer/Getty Images)

"When I work with young actresses, I'm so protective of them. There’s a lot of people who go, 'Oh, you’re only here because of your face.' And they belittle them because of the way that they look. I think everyone can be a little kinder."

Knightley's next role is set to be in the forthcoming Netflix spy thriller, Black Doves.

She will star as Helen, who embarks upon a passionate affair that may put her secret identity in jeopardy - as a result of her lover becoming victim to London’s criminal underworld, and her employers send an old friend in a bid to keep them safe.

Sarah Lancashire of Happy Valley and Ben Whishaw of This is Going to Hurt are also set to star.