Fans left speechless after discovering how old Keira Knightley really was in Pirates Of The Caribbean

Can you believe it’s been more than 20 years since Pirates of the Caribbean: The Curse of Black Pearl sailed onto our screens?

The swashbuckling Disney fantasy movie, starring Johnny Depp as the iconic Captain Jack Sparrow and Orlando Bloom as Will Turner, follows the pair as they attempt to rescue Elizabeth Swann - played by Keira Knightley - from the clutches of Captain Hector Barbossa (Geoffrey Rush).

Knightley - who had previously appeared in Star Wars: Episode I - The Phantom Menace, Bend It Like Beckham, and the 1999 Oliver Twist adaptation with Julie Walters - was cast as Swann due to her ‘indescribable quality reminiscent of motion picture stars from Hollywood's heyday’, according to director Gore Verbinski and producer Jerry Bruckheimer.

Decades later, Pirates of the Caribbean: The Curse of Black Pearl remains one of the star’s stand-out performances.

However, fans are only just realizing how young she actually was when she took on the massive role.

If you had to guess, how old would you say she was? Mid 20s? Early 20s? Well, either guess and you are well off. Knightley was actually only 17 when they began filming the flick.

One Twitter user wrote: “This must be a LIE,” while another wrote: “Wtf, I never knew.”

And a third wrote: “When I watched the movie I thought she was older than me.”

“Can you believe Keira Knightley was only 17 when Pirates of the Caribbean the Curse of the Black Pearl was filmed,” someone else said as they shared images of the star in the role.

“The fact Keira Knightley gave us these two iconic characters in the same year WHILE SHE WAS ONLY 17,” commented another referencing her being in Love Actually that same year.

Fans can't believe Keira Knightley was just 17 when she started filming for Pirates of the Caribbean in 2003 (Disney)

With the success of the first film and its subsequent sequels came fame and celebrity status - something the mother-of-two has spoken out about, arguing it hasn’t always been a good thing.

In a 2016 interview with Variety, the British star said: "I found it pretty horrific. 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. You’re in some ways still a child. It was traumatic, but it set up the rest of my career."

Despite the struggles then and the ones that followed in the next few years, the actress also said she wouldn’t take anything back.

“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," she confessed to the publication two years later.

"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.”